- The definition of which is what one(s) of those mentioned.
An example of which is what book or what shirt.
- Which is defined as identifying what one(s) out of a group.
An example of which is of a group of potential employees or of a selection of books.
which definition by Webster's New World
- what one (or ones) of the number of persons, things, or events mentioned or implied?: which of the men answered? which do you want?
- the one (or ones) that: he knows which he wants
- that: used as a relative referring to the thing, group, or event specified in the antecedent word, phrase, or clause: which can be used in a restrictive clause [the war which had just ended, the class to which he spoke], in a restrictive clause preceded by the pronoun that[he sacrificed that which he valued most], in a nonrestrictive clause [my car, which is not running; my family, in which she found a warm welcome], or, archaically, of a person [Our Father, which art in heaven]
- either, or any, of the persons, things, or events previously mentioned or implied; whichever: take which you prefer
- a thing or fact that: you are late—which reminds me, where were you yesterday?
Origin: Middle English whiche ; from Old English hwylc, hwelc, for an unverified form hwa-lic, literally , who like (akin to Gothic hwileiks, Old High German hwelīh, German welch): see who and amp; -ly
- what one or ones (of the number mentioned or implied): which man (or men) answered? which books did he choose?
- whatever; no matter what: try which method he pleased, he could not succeed
- being the one just mentioned: he is very old, which fact is important
which definition by American Heritage Dictionary
- What particular one or ones: Which of these is yours?
- The one or ones previously mentioned or implied, specifically:a. Used as a relative pronoun in a clause that provides additional information about the antecedent: my house, which is small and old.b. Used as a relative pronoun preceded by that or a preposition in a clause that defines or restricts the antecedent: that which he needed; the subject on which she spoke.c. Used instead of that as a relative pronoun in a clause that defines or restricts the antecedent: The movie which was shown later was better.
- Any of the things, events, or people designated or implied; whichever: Choose which you like best.
- A thing or circumstance that: He left early, which was wise.
- What particular one or ones of a number of things or people: Which part of town do you mean?
- Any one or any number of; whichever: Use which door you please.
- Being the one or ones previously mentioned or implied: It started to rain, at which point we ran.
Origin: Middle English, from Old English hwilc; see kwo- in Indo-European roots.Usage Note: The relative pronoun which is sometimes used to refer to an entire sentence or clause, rather than a noun or noun phrase, as in She ignored him, which proved to be unwise. They swept the council elections, which could never have happened under the old rules. While these examples are unexceptionable, using which in this way sometimes produces an ambiguous sentence. Thus It emerged that Edna made the complaint, which surprised everybody leaves unclear whether it was surprising that a complaint was made or that Edna made it. The ambiguity can be avoided with paraphrases such as It emerged that the complaint was made by Edna, a revelation that surprised everybody. • Which may be used to refer to an entire sentence or clause only when it is preceded by that sentence or clause. When the referent follows, what should be used, particularly in formal style: Still, he has not said he will withdraw, which is more surprising but Still, what (not which) is more surprising, he has not said he will withdraw. See Usage Notes at that, what, whose.