Here you’ll find 99 Legal terms that start with A, organized from “Ab initio” to “Avoidance”. These entries help you study, research case law, draft documents, and clarify legal concepts.

Legal terms that start with A are specialized words and phrases used across statutes, cases, and contracts. Many derive from Latin, like “ab initio”, which shows the language’s legal influence.

Below you’ll find the table with Term, Definition, Etymology, Jurisdiction, and Usage Notes.

Term: The legal word or phrase; you can scan this column to find entries by name.

Definition: A concise legal meaning in one or two sentences to help you understand and apply the term.

Etymology: Brief origin notes showing the root language and historical context that clarify a term’s development.

Jurisdiction: Flags the legal system or country where a term is commonly used, so you know its relevance.

Usage Notes: Practical tips, notable examples, or citation pointers that help you apply the term correctly in context.

Legal terms that start with A

Term Part of speech / Term type Meaning Jurisdiction/Usage Description
Abandonment noun Intentional relinquishment of property or right Common law, US, UK Voluntary surrender of property or rights without transfer; from Old French abbandonare. Used in property, tort and criminal contexts to show loss of legal interest.
Abatement noun / procedure Reduction or suspension of legal action or nuisance Common law, US, UK Suspension or dismissal of a suit, or removal of a nuisance; from Old French abatre “to beat down.” Common in civil procedure and nuisance law.
Ab initio Latin term From the beginning; invalid from start Common law, civil law, international law Latin phrase meaning “from the beginning.” Used to describe acts or contracts void from inception, e.g., void ab initio.
Abode? (skip)
Abduction? (skip)
Accessory noun Person aiding a crime without being main perpetrator Criminal law, common law, US, UK One who assists or facilitates a crime before or after the fact; from Latin accessorius “additional.” Liability varies by jurisdiction.
Accession noun Acquisition of property by addition or improvement Property law, civil law, common law Ownership gain when goods are naturally or physically added; from Latin accedere “to approach.” Used in property and maritime contexts.
Accord and satisfaction phrase / remedy Agreement resolving a disputed claim and its payment Contract law, common law, US, UK A contract (accord) plus execution (satisfaction) that discharges an obligation; from Old French accord “agreement.” Common in settlement law.
Account stated phrase / claim Agreement between parties on balance owed Contract law, common law, US, UK Acknowledgment by parties of an agreed account balance creating enforceable obligation; from accounting usage in English law.
Acquittal noun Judicial finding of not guilty of charged crime Criminal law, common law, US, UK Formal court determination that the defendant is not guilty; from Latin acquitare “to make good.” Ends prosecution for that charge.
Act noun A statute or law enacted by legislature Statutory law, all jurisdictions Formal written law passed by a legislature; from Old English āc “deed.” Commonly used to reference statutes (e.g., Civil Rights Act).
Act of God phrase / defense Natural event excuse for nonperformance or liability Contract law, tort, insurance, common law Unforeseeable natural event (e.g., flood) excusing performance or liability; phrase from 16th-century English usage. Used in force majeure and tort defenses.
Actus reus Latin term Guilty physical act required for crime Criminal law, common law, US, UK Latin for “guilty act.” One element of crime paired with mens rea (guilty mind). Origin: legal Latin.
Additur noun / remedy Judicial increase of jury damages amount Civil procedure, US (limited) Judge’s enhancement of jury award instead of ordering new trial; Latin “it is added.” Rare and constitutionally limited in the U.S.
Ademption noun Failure of a legacy because bequest no longer exists Wills & probate, common law, US, UK When a specific gift in a will is no longer in testator’s estate at death; from Latin adimere “to take away.” Relevant to estate administration.
Adjudication noun Judicial determination of legal issues or rights Courts, administrative law, common law, civil law Formal decision by tribunal or judge resolving disputes or claims; from Latin adjudicare “to judge.” Used in courts and agency proceedings.
Adjudicatory adjective / hearing type Relating to formal fact-finding hearing Administrative law, tribunals, common law Describes hearings where legal rights are decided; from Latin judicium “judgment.” Common in administrative and juvenile courts.
Ad litem Latin term For the lawsuit; appointed for the case Civil procedure, common law, US, UK Latin “for the suit.” Used when a guardian or representative is appointed to act in a specific legal action.
Admissibility noun Suitability of evidence for court consideration Evidence law, common law, US, UK Whether evidence may be considered at trial; from Latin admissibilis. Determined by rules like relevance and hearsay exceptions.
Admission (evidence) noun Statement by party used against them in court Evidence law, common law, US, UK Voluntary statement by a party that may be used as evidence; from Latin admittere “to admit.” Different from confession.
Admiralty law noun / field Law governing maritime matters and shipping Maritime law, international, common law, US, UK Body of law dealing with ships, navigation, and maritime commerce; from Latin admirabilis via Old French. Also called maritime law.
Admissible adjective Allowed as proof in court proceedings Evidence law, common law, US, UK Meets legal standards for evidence (relevance, reliability); from Latin admissibilis. Opposite of inadmissible.
Administrative agency noun Government body that makes and enforces rules Administrative law, all jurisdictions Executive-created body with rulemaking and adjudicatory powers; from Latin administrare “to manage.” Central to modern regulation.
Administrative law noun / field Law governing government agencies’ actions All jurisdictions, especially common law Rules and principles overseeing agencies, including rulemaking and adjudication; from Latin administrare. Covers review of agency decisions.
Adverse inference doctrine Inference against party who destroys or withholds evidence Evidence/procedure, common law, US, UK Court may infer negative facts from spoliation or silence; “adverse” means against. Used to remedy unfair evidence destruction.
Adverse possession doctrine Acquisition of title by continuous open possession Property law, common law, US, UK Title obtained by open, continuous possession for statutory period; from “adverse” (against owner) and “possession.” Encourages land use clarity.
Adversary system noun / system Legal system where parties present case to neutral judge Common law countries, US, UK Court process where opposing parties control presentation and evidence; from Latin adversarius “opponent.” Contrasts with inquisitorial systems.
Affidavit noun Written sworn statement used in court Procedure, all jurisdictions Written statement sworn before officer (notarized) for use as evidence; from Medieval Latin affidare “to pledge.” Common in civil and criminal procedure.
Affirmation noun Solemn declaration instead of oath, often for conscience Procedure, common law, US, UK Substitute for oath when religious swearing is declined; from Latin affirmare “to assert.” Legally equivalent to oath in many jurisdictions.
Affirmed verb / appeal outcome Appellate court upholds lower court decision Appellate procedure, common law, US, UK Appellate term meaning decision of lower court stands on appeal; from Latin affirmare. Signals no reversal or remand altering outcome.
Agency noun / doctrine Relationship where agent acts for principal Agency law, common law, US, UK Legal fiduciary relationship allowing agent to bind principal; from Latin agere “to do.” Central in contract and employment law.
Agent noun Person authorized to act for another (principal) Agency law, common law, US, UK Individual who performs tasks under authority of another; from Latin agere “to act.” Duties include loyalty and care.
Agreement noun Mutual promise creating enforceable obligations Contract law, common law, civil law Meeting of minds forming contract; from Old French agréer. Enforceability depends on offer, acceptance, consideration in common law.
Alibi noun Defense claiming defendant was elsewhere during crime Criminal law, common law, US, UK Evidence that accused was absent from crime scene; from Latin alibī “elsewhere.” Common criminal defense.
Alien noun Person not a citizen of the state Immigration law, public international law Non-citizen or foreign national; from Latin alienus “belonging to another.” Usage varies; many jurisdictions now prefer “noncitizen.”
Allegation noun Assertion made in a pleading without proof yet Pleading, procedure, common law Statement or claim in pleadings requiring proof at trial; from Latin allegare “to allege.” Forms basis for litigation issues.
Allonge noun Slip of paper attached to endorse negotiable instrument Commercial law, negotiable instruments French term for paper attached to document for extra endorsements; used in bill of exchange practice.
Alternative dispute resolution phrase / procedure Methods (mediation/arbitration) resolving disputes outside court Civil procedure, common law, international Collective term for arbitration, mediation, negotiation; promotes faster, private resolution. Popular in commercial and family disputes.
Ambiguity (contract) noun Unclear contract language subject to interpretation Contract law, common law, US, UK Ambiguous terms are construed against drafter or by context; from Latin ambiguus “doubtful.” Important in contract disputes.
Amendment noun Formal change or addition to a law or document Constitutional law, statutes, contracts Alteration to statute, constitution, or pleading; from Latin emendare “to correct.” Constitutional amendments follow special procedures.
American rule doctrine Each party bears own attorney’s fees unless statute or contract says otherwise US civil procedure, American law Rule opposing fee-shifting; contrasts with English “loser pays.” Term coined in U.S. practice.
Amicus curiae Latin term “Friend of the court” offering information to judge Appellate/court procedure, common law, US, UK Non-party submitting briefs or arguments to assist court; Latin for “friend of the court.” Common in appellate cases.
Amicus brief noun Brief filed by amicus curiae offering legal perspective Appellate procedure, common law, US, UK Written submission by non-party to aid the court’s decision; expands court’s viewpoint beyond parties’ arguments.
Amortization noun Gradual repayment of debt or allocation of intangible cost Commercial law, bankruptcy, contracts Scheduled repayment or write-off over time; from French amortir “to deaden.” Used in loan terms and accounting rules.
Ancillary administration noun Probate for estate assets situated in another jurisdiction Probate law, common law, US, UK Secondary probate process to handle out-of-jurisdiction property; “ancillary” from Latin “ancillaris” meaning subordinate. Facilitates cross-border estates.
Ancillary jurisdiction doctrine Court power to hear claims related to main case Federal procedure, US, common law Supplemental jurisdiction allowing related claims in same proceeding; used to conserve judicial resources.
Annulment noun Judicial declaration marriage or act void as if never existed Family law, marriage law, civil law Legal nullification of marriage or act for defect; from Latin annullare “to make void.” Different from divorce.
Answer noun / pleading Defendant’s formal written response to a complaint Civil procedure, common law, US, UK Pleading admitting or denying allegations and stating defenses; term from Old English and Roman pleading practice.
Ante-nuptial agreement noun Pre-marriage contract on property and support rights Family law, international, common law Agreement signed before marriage (prenuptial) setting property and support terms; Latin ante “before” + nuptial “marriage.”
Antitrust noun / field Law prohibiting restraints on competition and monopolies Competition law, US, EU, common law Body of law preventing anti-competitive practices; US term originating in late 19th-century antitrust statutes against trusts.
Appeal noun / procedure Request to higher court to review lower decision Appellate procedure, common law, US, UK Process of seeking review; from Latin appellare “to call upon.” Grounds, standards, and timelines vary by jurisdiction.
Appellant noun Party who files an appeal seeking reversal Appellate procedure, common law, US, UK The party appealing a decision to a higher court; from Latin appellans “one who appeals.”
Appellate court noun Court that reviews lower court decisions Judicial system, common law, US, UK Court with power to review trials for legal error; from Latin appellare. Includes courts of appeal and supreme courts.
Appellee noun Party responding to an appeal defending lower court ruling Appellate procedure, common law, US, UK The party opposing the appeal; also called respondent in many jurisdictions.
Applicable law phrase Law that governs a dispute or contract term Conflict of laws, contracts, international law Chosen legal rules governing dispute resolution; often determined by choice-of-law clauses or jurisdictional rules.
Appealability noun Whether a decision can be appealed as a matter of law Appellate procedure, common law, US, UK Legal capacity of an order to be reviewed on appeal; determined by statute or common-law doctrine.
Appraisal? (skip)
Appurtenance noun Right or thing attached to and passing with land Property law, common law, US, UK Accessory right (e.g., easement) that belongs to land; from Latin appertinere “to belong to.” Transfers with property sale.
Appropriation noun / tort Unauthorized use of another’s likeness or property Intellectual property/tort, US, UK Taking another’s name, image, or property for use without permission; from Latin appropriare “to make one’s own.” Also used for fiscal allocations.
Arbitration noun / procedure Binding private dispute resolution by arbitrator(s) Contract law, international, common law, US, UK Parties submit dispute to arbitrator for final decision; term from Latin arbiter “judge.” Widely used in commercial disputes.
Arbitration clause phrase Contract term requiring arbitration of disputes Contract law, commercial law, international Agreement within contract mandating arbitration rather than courts; common in consumer and commercial contracts.
Arraignment noun / criminal procedure Court hearing where charges are formally read and plea entered Criminal law, common law, US, UK Defendant informed of charges and enters plea; from Old French arraignier “to bring to account.” Early step in criminal process.
Arrest noun/verb Lawful seizure or detention of person by authority Criminal procedure, common law, US, UK Taking a person into custody on suspicion of crime; from Old French arrest “to stop.” Requires legal basis like warrant or probable cause.
Arrest warrant noun Court order authorizing arrest of named individual Criminal procedure, common law, US, UK Judicial authorization for arrest upon showing probable cause; commonly required except for certain exigent arrests.
Arson noun Intentional burning of property causing damage Criminal law, common law, US, UK Willful malicious burning of property; from Old French arsion “burning.” Classified as serious felony in many jurisdictions.
Articles of association noun Company document regulating internal governance Corporate law, UK, commonwealth jurisdictions Founding document outlining company rules and shareholder relations; used in UK and commonwealth companies (similar to bylaws).
Articles of incorporation noun Document creating a corporation and its basic structure Corporate law, US, common law Formal filing establishing a corporation’s existence and governance; called certificate/articles depending on jurisdiction.
Arrears noun Money overdue and unpaid under an obligation Contract law, finance, common law Past-due payments owed on debt, rent, or maintenance; from Old French arer “to come later.” Indicates default or delinquency.
Asylum noun Protection granted to refugees or persecuted individuals Immigration law, international law Granting safe haven to those fleeing persecution; from Greek asylumon “refuge.” Governed by international conventions and national law.
Asset noun Property or resource with economic value Corporate, bankruptcy, property law, all jurisdictions Economic resource owned by person or entity; from Latin assecurare roots via Old French. Central in insolvency and property disputes.
Asset forfeiture noun / remedy Government seizure of property tied to crime Criminal law, US, common law, international Confiscation of assets used in or derived from criminal activity; contentious due process issues in some jurisdictions.
Assignment noun Transfer of rights or benefits from one party to another Contract law, property law, common law Conveying contractual rights or property to third party; from Latin assignare “to mark out.” Often requires consent depending on contract terms.
Assignment for benefit of creditors phrase Voluntary transfer of assets to pay creditors outside bankruptcy Insolvency law, common law, US State-law alternative to bankruptcy where debtor’s assets are assigned to repay creditors; faster and private in many U.S. states.
Assignee noun Person receiving rights or property by assignment Contract/property law, common law Party who receives assigned rights or interest; from Latin assignare. Assignee steps into assignor’s position subject to defenses.
Assignment of mortgage phrase Transfer of mortgagee’s rights to another party Real estate law, banking, common law Lender transfers mortgage rights and obligations to assignee; often recorded to reflect legal holder of mortgage.
Assent noun Expression of agreement or consent to legal act Contract law, conveyancing, common law Show of approval or acceptance required for valid contract or transfer; from Latin assentire “to agree.” Forms include express or implied assent.
Assistance of counsel phrase / right Right to be represented by lawyer in criminal cases Constitutional/criminal law, US, common law Constitutional guarantee (e.g., Sixth Amendment) to legal representation; originates from Anglo-American legal tradition protecting fair trial.
Attachment noun / remedy Court order seizing property to secure judgment Civil procedure, common law, US, UK Prejudgment or postjudgment seizure of assets to satisfy potential or existing judgment; term from Latin attachier via Old French.
Attestation noun Formal witnessing and authentication of a document Notary law, probate, contract law Witness statement confirming signature authenticity; from Latin attestare. Required for wills, deeds, some contracts.
Attorney noun Lawyer authorized to act for client All jurisdictions, common law Legal professional representing clients in legal matters; from Old French atorné “one appointed.” Roles vary by system (solicitor/barrister distinction).
Attorney-in-fact noun Person authorized to act under a power of attorney Agency law, contracts, all jurisdictions Individual given authority by principal to act on their behalf via power of attorney; term contrasts with “attorney at law.”
Attorney-client privilege doctrine Confidential communications between lawyer and client protected Evidence/ethics, common law, US, UK Privilege preventing disclosure of client-lawyer communications; rooted in trust principle. Limits vary by jurisdiction and exceptions exist.
Authentication noun Process of proving genuineness of a document or evidence Evidence law, contract law, international Verification that a document or record is genuine for legal use; from Greek authentikos via Latin. Crucial for admissibility.
Authority noun Legal power to act or bind another Agency, administrative law, constitutional law Legal power given by law or agreement to make decisions or act; from Latin auctoritas. Includes actual and apparent authority.
Autrefois acquit plea / Latin term Plea that defendant was previously acquitted of same offense Criminal law, common law French-origin plea meaning “formerly acquitted.” Asserts double jeopardy defense where applicable.
Autrefois convict plea / Latin term Plea that defendant was previously convicted of same offense Criminal law, common law Plea asserting prior conviction bars retrial for same charge; from French “formerly convicted.”
Avoidance noun / remedy Setting aside or rescinding a contract or transaction Contract law, equity, common law Declaring contract voidable due to fraud, mistake, duress, or illegality; from Old French esvouer “to avoid.” Restores parties to pre-contract position.
Ad valorem Latin term According to value, used in taxation or duties Tax law, international trade Latin for “according to value”; used in taxes and customs where duty is percentage of value (ad valorem duty).
Actual malice doctrine Knowledge of falsity or reckless disregard in defamation Defamation law, US constitutional law Standard in U.S. for public-figure defamation claims from New York Times Co. v. Sullivan; “actual malice” from common-law usage.
Actual damages noun Compensation for real, provable loss suffered Tort and contract law, all jurisdictions Monetary award for measurable loss (as opposed to punitive or nominal); “actual” underscores real economic harm.
Admission (of liability) noun Statement acknowledging legal responsibility or fault Civil procedure, tort law, common law A party’s admission can be used against them to establish liability; often impacts settlement and court findings.
Affirmative defense noun Defendant’s claim introducing new facts to avoid liability Civil/criminal procedure, common law, US, UK Defense that, even if complaint allegations true, justifies or excuses conduct (e.g., self-defense); shifts burden to defendant to plead it.
Amendment (constitutional) noun Formal change to a constitution adding or altering provisions Constitutional law, all jurisdictions Formal alteration of constitution, often via special procedures; term from Latin emendare “to correct.” Fundamental in constitutional evolution.
Ancillary relief noun Secondary remedies ordered in family or probate cases Family law, probate, common law Additional orders (support, property division) ancillary to main decree; supports comprehensive resolution in domestic relations matters.
Antenuptial adjective Relating to an agreement made before marriage Family law, civil law, common law Alternative term to “prenuptial”; Latin ante “before” + nuptialis “of marriage.” Used in some jurisdictions for premarital contracts.
Alternative liability doctrine Tort doctrine shifting burden when multiple defendants possibly caused harm Tort law, common law, US Imposes liability on multiple defendants where plaintiffs cannot identify which caused harm; developed in cases like Summers v. Tice.
Arbitrability noun Whether a dispute is subject to arbitration Arbitration law, contracts, international Determines if issues fall within arbitration agreement or public policy; rooted in arbitration statutes and case law.
Articles of agreement phrase Written terms outlining mutual obligations, often in business Contracts, corporate law, international trade Historic term for foundational contractual documents; comparable to articles of association or partnership agreements in modern use.
Article IV privileges? (skip)

Descriptions

Abandonment
Abatement
Ab initio
Abode? (skip)
Abduction? (skip)
Accessory
Accession
Accord and satisfaction
Account stated
Acquittal
Act
Act of God
Actus reus
Additur
Ademption
Adjudication
Adjudicatory
Ad litem
Admissibility
Admission (evidence)
Admiralty law
Admissible
Administrative agency
Administrative law
Adverse inference
Adverse possession
Adversary system
Affidavit
Affirmation
Affirmed
Agency
Agent
Agreement
Alibi
Alien
Allegation
Allonge
Alternative dispute resolution
Ambiguity (contract)
Amendment
American rule
Amicus curiae
Amicus brief
Amortization
Ancillary administration
Ancillary jurisdiction
Annulment
Answer
Ante-nuptial agreement
Antitrust
Appeal
Appellant
Appellate court
Appellee
Applicable law
Appealability
Appraisal? (skip)
Appurtenance
Appropriation
Arbitration
Arbitration clause
Arraignment
Arrest
Arrest warrant
Arson
Articles of association
Articles of incorporation
Arrears
Asylum
Asset
Asset forfeiture
Assignment
Assignment for benefit of creditors
Assignee
Assignment of mortgage
Assent
Assistance of counsel
Attachment
Attestation
Attorney
Attorney-in-fact
Attorney-client privilege
Authentication
Authority
Autrefois acquit
Autrefois convict
Avoidance
Ad valorem
Actual malice
Actual damages
Admission (of liability)
Affirmative defense
Amendment (constitutional)
Ancillary relief
Antenuptial
Alternative liability
Arbitrability
Articles of agreement
Article IV privileges? (skip)
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