what one?: Which of these do you want? Which do you want?
2.
whichever: Choose which appeals to you.
3.
(used relatively in restrictive and nonrestrictive clauses to represent a specified antecedent): The book, which I read last night, was exciting. The socialism which Owen preached was unpalatable to many. The lawyer represented five families, of which the Costello family was the largest.
4.
(used relatively in restrictive clauses having that as the antecedent): Damaged goods constituted part of that which was sold at the auction.
5.
(used after a preposition to represent a specified antecedent): the horse on which I rode.
6.
(used relatively to represent a specified or implied antecedent) the one that; a particular one that: You may choose which you like.
7.
(used in parenthetic clauses) the thing or fact that: He hung around for hours and, which was worse, kept me from doing my work.
8.
Nonstandard. who or whom: a friend which helped me move; the lawyer which you hired.
–adjective
9.
what one of (a certain number or group mentioned or implied)?: Which book do you want?
10.
whichever; any that: Go which way you please, you'll end up here.
11.
being previously mentioned: It stormed all day, during which time the ship broke up.
Origin: bef. 900; ME; OE hwilc, hwelc, equiv. to hwe- (base of hwāwho) + -līc body, shape, kind (see like1); c. OFris hwelik, D welk, G welch, Goth hwileiks lit., of what form
Usage note: The relative pronoun which refers to inanimate things and to animals: The house, which we had seen only from a distance, impressed us even more as we approached. The horses which pulled the coach were bay geldings. Formerly, which referred to persons, but this use, while still heard (a man which I know), is nonstandard. Contrary to the teachings of some usage guides, which introduces both restrictive and nonrestrictive clauses. The “rule” that which can be used only with nonrestrictive clauses has no basis in fact. In edited prose three-fourths of the clauses in which which is the relative pronoun are restrictive: A novel which he later wrote quickly became a bestseller. See also that.
What particular one or ones: Which of these is yours?
The one or ones previously mentioned or implied, specifically:
Used as a relative pronoun in a clause that provides additional information about the antecedent: my house, which is small and old.
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.
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.
adj.
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.
[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.
[hwich, wich] 
