... Uh, no.
All information except definitions of which taken from OWL at Purdue. Examples are mine, but everything I learned came from OWL. It's one of my favorite sites. Shouldn't it be one of yours, too?
Which as a Pronoun:
In a relative clause:
As a pronoun, it is used in relative clauses or as the object of a preposition. To be specific, which is a relative pronoun, or a pronoun which introduces a relative clause. Other examples are who, whom, whoever, whomever, whose, and that.
A relative clause is a phrase that modifies a word, phrase, or idea. The word, phrase, or idea is called the antecedent. We'll illustrate with my cat, Bard.
|Also, I misspelled "antecedent." Whoops.|
That is a pronoun that replaces bird, and "that Bard caught" modifies bird. Therefore, bird is the antecedent, because it is the word being modified, and "that Bard caught" is the relative clause.
The mouse, which Bard ate, had destroyed my cheese.
"which Bard ate" is the relative clause, with which being the relative pronoun that replaces mouse. Mouse is therefore the antecedent, being modified by "which Bard ate."
Note: Why did I use which in one example, and that in the other? Because in the latter example, which Bard ate is a non-restrictive clause: there is only one mouse to which I could be referring. In the former, that Bard caught is a restrictive clause: there are lots of birds, so I had to specify which one Bard caught. Restrictive/non-restrictive clauses don't mean the same thing as relative clauses, but sound enough alike that they're easily confused. Read up on that vs. which to compare!
Which as the object of a preposition
The barn at which I threw the baseball was blue.
The dragon with which I ate lunch smelled bad.