which

The word “which” means used to ask someone to specify one or more people or things from a known set. In plain terms, a word for picking out one option from a group, or for adding extra detail about something already named.

“Which” is pronounced wihch (/wɪt͡ʃ/ in IPA).

Here is “which” used in a sentence: “Which coat is yours, the black one or the grey one?”

Depending on how it is used, “which” can be a det and a pronoun.

The word “which” comes from Old English. From Old English hwelc, literally "of what kind" — built from the same root as "who" and "what".

“Which” is a very common word in modern English, usually learned at around the A1 level.

“Which” has 2 distinct senses listed in this dictionary. The most common is: used to ask someone to specify one or more people or things from a known set.

In American English, "that" introduces essential (restrictive) information ("the report that I wrote"), while "which" introduces extra, non-essential information set off by commas ("the report, which took weeks, was approved"). British English uses "which" more freely for both, but the comma rule for non-essential clauses applies everywhere.

Use a comma when "which" adds extra information the sentence could survive without ("the car, which was red, sped off"). No comma is needed when "which" asks a question ("which one is yours?") or when the clause is essential to identifying the noun.

Use "which" when choosing from a known or limited set ("which of these three do you want?") and "what" when the options are open-ended ("what do you want for dinner?"). The boundary is soft, but "which" always implies the speaker has a specific set of options in mind.

In modern English, "who" refers to people and "which" to things ("the man who called," "the book which I read"). "Which" can, however, apply to people when selecting one from a set, as in "which of the candidates won?"