Definitions
1.ConjunctionAnd."They only offered me five dollars, which I wouldn’t do it for less than fifteen."
2.DeterminerWhat, of those mentioned or implied."Which song shall we play?; They couldn't decide which song to play.; Which one is bigger?; Show me which one is bigger."
3.DeterminerThe/Any ... that; whichever."Take which one you want.; You may go which way you please."
4.DeterminerDesignates the one(s) previously mentioned."He once owned a painting of the house, which painting would later be stolen.; She only speaks Chinese, which language I can hardly follow.; For several seconds he sat in silence, during which time the tea and sandwiches arrived.; I'm thinking of getting a new car, in which case I'd get a red one."
5.PronounWhat one or ones (of those mentioned or implied)."Which is which?; By now, you must surely know which is which.; Which is bigger, the red one or the blue one?; I'm unable to determine which is bigger.; Which's your spouse? -The one in trousers."
6.PronounThe/Any ones that; whichever."Please take which you please."
7.PronounIn a non-restrictive relative clause, referring to something previously mentioned.
Referring to a preceding noun."I dropped a saucepan, which knocked over the eggs, which went all over the kitchen floor.; I found my camera, which I thought I'd lost, under the bed.; I entered the room, at the far end of which was a small table.; She had a young child, which cried incessantly.; The front door was open, which concerned me.; He had to leave, which was very difficult.; She saved my life, for which I am eternally grateful."
8.PronounReferring to a preceding noun."I dropped a saucepan, which knocked over the eggs, which went all over the kitchen floor.; I found my camera, which I thought I'd lost, under the bed.; I entered the room, at the far end of which was a small table.; She had a young child, which cried incessantly."
9.PronounUsed of people (now generally who, whom, that; which remains possible with words also referred to by it such as baby, child)."She had a young child, which cried incessantly."
10.PronounReferring to a preceding statement."The front door was open, which concerned me.; He had to leave, which was very difficult.; She saved my life, for which I am eternally grateful."
11.PronounIn a restrictive relative clause, referring to a noun previously mentioned."This is the letter which I received.; This is the letter in which he explains his decision."
12.PronounUsed of people.