This page lists 12 conjunctions that start with the letter O, running from “or” to “owing to the fact that”. The list includes single words and longer phrases, and each one links ideas in a different way. You can use them to offer choices, set conditions, add a correction, or explain a reason.

Conjunctions are words or phrases that join words, clauses, or sentences and show how the ideas relate to each other. Teachers often use the memory aid FANBOYS to help students recall the seven main coordinating conjunctions, and “or” is one of them.

Below you’ll find the table with the conjunction, its definition, an example usage, and a short description.

Conjunction: the word or phrase itself, listed in alphabetical order, so you can quickly find the exact term you want to look up.

Definition: a short, plain explanation of what the conjunction means and which type it is, so you know when it fits your sentence.

Example usage: a complete sentence that shows the conjunction in action, giving you a model you can copy or adapt in your own writing.

Description: a few extra details about tone, formality, and common use, helping you choose the right option for casual speech or formal writing.

Conjunctions

ConjunctionDefinitionExample usage
orA coordinating conjunction that presents an alternative or choice between options.Would you like tea or coffee?
onceA subordinating conjunction meaning “as soon as” or “after the moment that.”Once the rain stops, we will head outside.
onlyA conjunction used informally to mean “but” or “except that,” introducing a restriction or contrast.I would go with you, only I have to work late.
only ifA subordinating phrase that sets a required condition for something to happen.You can enter only if you have a ticket.
only whenA subordinating phrase that limits an action to a specific moment or circumstance.The alarm sounds only when someone opens the back door.
otherwiseA conjunctive adverb meaning “if not” or “or else,” showing the result of a different situation.Take your umbrella; otherwise, you will get soaked.
or elseA phrase that links a command or situation to a negative consequence.Finish your homework, or else you can’t go to the party.
or ratherA phrase used to correct or refine what was just said.He lives in London, or rather, just outside it.
on condition thatA subordinating phrase meaning “provided that,” stating a requirement.You may borrow my car on condition that you return it by noon.
on the other handA transitional phrase that introduces a contrasting point or alternative view.The apartment is cheap; on the other hand, it is far from the city center.
on the contraryA transitional phrase used to directly oppose or contradict a previous statement.I’m not upset; on the contrary, I’m delighted.
owing to the fact thatA subordinating phrase meaning “because,” introducing a reason.The match was canceled owing to the fact that the pitch was flooded.

Descriptions

or
One of the most common conjunctions in English. It links words, phrases, or clauses to show a choice, and it is a member of the FANBOYS group of coordinating conjunctions.
once
Once links a time condition to a main action. It signals that the second event follows right after the first one is completed.
only
Used mostly in casual speech and writing, only adds a limiting detail to what was just said. It works much like “but” with a slightly regretful tone.
only if
This phrase makes a condition strict. The main action is allowed or true in no other circumstance than the one stated.
only when
It narrows a statement so the action happens in one situation and no other. It is common in rules, instructions, and explanations.
otherwise
Otherwise introduces what would happen if the earlier condition were not met. It is often used after a semicolon or full stop to link two ideas.
or else
Or else warns of what will follow if something is not done. It can sound firm or even threatening, so it suits informal and direct speech.
or rather
This phrase lets a speaker adjust a statement to make it more accurate. It adds a quick correction without starting over.
on condition that
A somewhat formal phrase used to set terms for an agreement or permission. It is close in meaning to “provided that” and “as long as.”
on the other hand
Writers use this phrase to present the opposing side of a comparison. It is often paired with “on the one hand” to balance two ideas.
on the contrary
It shows that the opposite of what was just said is true. It is stronger than “however” because it denies the earlier point instead of just contrasting it.
owing to the fact that
A formal and wordy way to say “because.” It appears mostly in official or written contexts, where “because” or “since” would usually be simpler.
If you think there is a missing term, let us know using the contact form.