Here you’ll find 24 Prefixes that start with I, organized from “iatro-” to “italo-“. They mainly derive from Latin or Greek and serve medical, numeric, spatial, and general word-building uses. This selection prioritizes common, high-utility prefixes first, followed by technical or specialized forms.

Prefixes that start with I are short affixes placed before a root to change or refine a word’s meaning. Many come from Latin or Greek, and some like “iatro-” reflect long-standing medical naming traditions.

Below you’ll find the table with Prefix, Origin, Meaning, Example words, Notes, and Sources.

Prefix: Shows the prefix form so you can spot the exact string used before roots and compare variants.

Origin: Gives the linguistic source, like Latin or Greek, so you understand the historical roots of meaning.

Meaning: Provides a concise gloss of the prefix in three to seven words, letting you grasp its basic contribution to a word.

Example words: Lists two to four clear examples so you see how the prefix changes or clarifies real vocabulary you know.

Notes: Highlights usage quirks, variant spellings, and register so you know when and how to apply the prefix correctly.

Sources: Points to reputable reference entries and glossaries so you can verify meanings and explore further etymology when needed.

Prefixes that start with I

PrefixOriginMeaningExample words
in-Latin in-not; in/into (negative or directional)inactive, import, illegal, irregular
inter-Latin inter-between, amonginternational, internet, interpersonal, intercede
intra-Latin intra-within, insideintramural, intranet, intravenous, intrastate
intro-Latin intro-inward, intointroduce, introspect, introvert, introversion
infra-Latin infra-below, beneathinfrastructure, infrared, infrasonic, infrahumans
iso-Greek isosequal, sameisotope, isometric, isothermal, isobar
idio-Greek idiosown, peculiar, distinctidiosyncrasy, idiomatic, idiopathic, idiolect
iatro-Greek iatrosphysician, medical treatmentiatrogenic, iatrology, iatrochemistry
ichthy-Greek ichthysfishichthyology, ichthyosis, ichthyosaur
ichno-Greek ichnostrack, traceichnology, ichnofossil
iodo-Greek iōd-containing iodine; violet-colorediodoform, iodide, iodination
ipso-Latin ipseself, itselfipso facto, ipsilateral, ipso jure
immuno-Latin immunis (Med Lat)immune, protectionimmunology, immunization, immunodeficiency
indo-Latin IndusIndia, Indian; relating to South AsiaIndo-European, Indo-Pacific, Indo-Aryan
italo-Latin ItaliaItaly, ItalianItalo-Romance, Italo-disco, Italo-American
ileo-Latin ileumileum (part of small intestine)ileostomy, ileocecal, ileal
ilio-Latin iliumilium (pelvic bone, hip)iliopsoas, iliofemoral, iliac
ideo-Greek ideaidea, thoughtideology, ideogram, ideological
ischio-Greek ischionischium (lower pelvis)ischiadic, ischiofemoral, ischium
irido-Greek iris/irid-iris (eye), rainbow-likeiridectomy, iridology, iridocyclitis
igni-Latin ignisfireignite, igneous, ignition
imino-Neo-Latin imino-relating to the =NH functional groupimino acid, imino group, iminopeptide
iono-Greek ionion, charged particleionosphere, ionotropic, ionogram
ideo-Greek ideaidea, thoughtideology, ideograph, ideological

Descriptions

in-
Very common Latin prefix with two senses: negation and motion/location. Variants im-, il-, ir- appear before consonants by assimilation.
inter-
Used for relations, exchange, or position between things; very productive in compounds.
intra-
Marks containment or internal location; common in medicine, organizations, and tech.
intro-
Denotes inward direction or entry; overlaps with intra- but often implies movement toward the inside.
infra-
Used in formal, legal, and scientific contexts; also appears in citations (“infra”).
iso-
A staple scientific prefix denoting equality or sameness; combines with many Greek roots.
idio-
Marks individuality or self-contained quality; common in linguistics and medicine.
iatro-
Medical combining form used to indicate physician-related causes, treatments, or theories.
ichthy-
Forms zoological and medical words related to fish; variant ichthyo- occurs with vowel-initial elements.
ichno-
Specialist prefix in paleontology and sedimentology referring to tracks, traces, and trace fossils.
iodo-
Chemical prefix indicating substitution by iodine or compounds related to iodine; used in organic nomenclature.
ipso-
Meaning “itself” or “by the fact itself”; appears as a fixed phrase and in compounds like ipsilateral.
immuno-
Widespread in biology and medicine to indicate immunity or immune-related systems and processes.
indo-
Geographical/ethnographic combining form used in historical linguistics and regional names.
italo-
Used in linguistic and cultural compounds; often capitalized when referring to the country or people.
ileo-
Anatomical combining form; common in medical terminology. Distinct from ilio- (ilium).
ilio-
Anatomical prefix for pelvic/hip-related structures; easily confused with ileo- (ileum).
ideo-
Used for words about ideas, beliefs, and conceptual systems; ideo- often precedes -logy/-graphy.
ischio-
Medical/anatomical combining form referring to the ischial region of the pelvis.
irido-
Eye-related medical prefix; also used for iridescent, rainbow-like qualities in other contexts.
igni-
Root/combining form for fire-related words; more of a root than a freely productive prefix, but widely attested.
imino-
Chemistry prefix denoting the imino functional group; common in organic nomenclature.
iono-
Used in physics and chemistry to form terms dealing with ions or ionized layers/behaviors.
ideo-
(Duplicate entry avoided in practice; included here only once) Used for concepts, beliefs, and conceptual systems.
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