What does when mean?
“When” is a basic English function word used chiefly to connect a main clause with a subordinate clause that specifies time or circumstance. In “Call me when you arrive,” it means “at the time when” and is therefore a conjunction. In the question “When does the shop open?”, it is an interrogative or temporal adverb asking for a point or period of time. The word can also introduce a condition, as in “When you are tired, take a break,” where it means “if.” In a relative clause, it identifies the occasion associated with an event: “I remember the day when we met.” Less commonly, it functions as a pronoun in phrases such as “Tell me when you’re ready.” A rare noun use appears in expressions such as “the whens and whys,” usually discussing the timing or circumstances behind an event. Its simplicity and flexibility make it essential in everyday speech, formal writing, questions, conditions, and narrative descriptions of time.
Introduces a clause expressing the time at which an event or circumstance occurs; in some contexts, it expresses a condition meaning “if.”
"We will leave when the concert ends."
The temporal use is dominant. In conditional contexts, “when” can overlap with “if,” especially for situations expected actually to occur.
Asks at what time or on what occasion something happens, or places an event in relation to another event.
"When will the results be announced?"
This includes interrogative and relative temporal uses, such as “the year when we met.”
Stands for the time or occasion of an event, especially in an expression directed to another person.
"Let me know when you have arrived."
This use is common in conversational and informal contexts.
A time, occasion, or circumstance, now chiefly found in fixed expressions about the timing or reasons for something.
"The article examines the whens and whys behind the decision."
This is an uncommon and mainly literary use.
Rare; the plural usually appears in expressions such as “the whens and whys.”
"The interview explores the whens and whys of the project."
From Old English hwanne to modern questions such as “when?” and “why?”: one little word carries the whole interrogative family.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does when come from?
Modern “when” comes from Old English hwanne, meaning “when” or “at the time when,” and is generally traced to a Proto-Germanic adverbial formation related to the interrogative element *hwaz, “who” or “what.” This element ultimately belongs to the same broad Indo-European interrogative family that produced English “what,” “why,” “whence,” and “where.” The word has remained in continuous English use since the Old English period, while its grammatical use expanded over time to include conditional, interrogative, relative, and pronominal functions.
Related word forms
How when is actually used
“When” is neutral in register and is used far more often as a conjunction or adverb than as a pronoun or noun. In conditional clauses, “when” can sometimes be exchanged with “if,” although “if” generally presents a hypothetical condition more explicitly.
Easily confused with when
“When” usually refers to the time of an event, while “if” presents a condition or possibility.
“When” identifies the time or circumstances of something, whereas “then” indicates a result or what happens next.