Relative pronoun

A relative pronoun (/ˈrelətɪv ˈprəʊnaʊn/) is a pronoun that is used to repeat the meaning of a previously mentioned noun. At the same time, it connects a relative clause to the sentence, acting both as a conjunction and a pronoun.

The relative pronouns are all the wh- words, except what (which must be used instead) plus that. Some grammar analysis also recognises a zero relative pronoun.

Form

Table

Relative pronoun	Used for	Example(s)	Notes
that	all	He is the man that I love.	Can only be used with defining relative clauses and not non-defining relative clauses. May require the use of a preposition.
Zero relative pronoun	all	“He is the man ∅ I love.”	Can only be used in object-defining relative clauses. In our example, the zero relative pronoun is represented by ∅.
which	Things		May require the use of a preposition.
who	People		Can be used in both subject- and object-defining relative clauses; in object-defining relative clauses whom is an alternative.
whom	People	Obama is a man whom people admire	Can only be used in an object-defining relative clause.
whose	Possession	Daniel, whose car was expensive, was very handsome.

Misunderstanding

There is a commonly-held belief that whose can only be applied to people, not to things. This is not so, however, and in the words of the deceased H. W. Fowler: “Let us, in the name of common sense, prohibit the prohibition of whose inanimate; good writing is surely difficult enough without the forbidding of things that have historical grammar, and present intelligibility, and obvious convenience, on their side.” Modern English Usage (1926)