<p><strong>pronoun</strong></p><ul><li>what one?: Which of these do you want?</li><li>Which do you want?</li><li>whichever; any one that: Choose which appeals to you.</li><li>(used relatively in restrictive and nonrestrictive clauses to represent a specified antecedent): The book, which I read last night, was exciting.</li><li>The socialism which Owen preached was unpalatable to many.</li><li>The lawyer represented five families, of which the Costello family was the largest.</li><li>(used relatively in restrictive clauses having that as the antecedent): Damaged goods constituted part of that which was sold at the auction.</li><li>(used after a preposition to represent a specified antecedent): the horse on which I rode.</li><li>(used relatively to represent a specified or implied antecedent) the one that; a particular one that: You may choose which you like.</li><li>(used in parenthetic clauses) the thing or fact that: He hung around for hours and, which was worse, kept me from doing my work.</li><li>Nonstandard. who or whom: a friend which helped me move; the lawyer which you hired.</li></ul><p><strong>adjective</strong></p><ul><li>what one of (a certain number or group mentioned or implied)?: Which book do you want?</li><li>whichever; any that: Go which way you please, you'll end up here.</li><li>being previously mentioned: It stormed all day, during which time the ship broke up.</li></ul>