Meaning of which in English
Interrogative adjective
1. being what one or ones out of these or those
Which book is yours? ー Which is your book?
I was there for an hour, during which time I saw nobody.
Take whichever seat you like.
Interrogative pronoun
1. what one or ones out of these or those, used to ask about a choice of things
Which is your book? ー Which book is yours?
1. ｟in restrictive use｠ used to introduce a clause that defines a word before it; that
This is the house which Washington lived in. ー This is the house in which Washington lived. ー This is the house where Washington lived.
2. ｟in non-restrictive use｠ and/but it[this, that]; a thing which
There is a big tree in the garden, which was planted by my grandpa.
3. the one that; any that; whichever
Choose which (of the books) you want.