RELATIVE CLAUSE In grammatical description, the term for a CLAUSE introduced by a relative word or a phrase containing a relative word. There are three types of relative clause: the adnominal relative clause; the sentential relative clause; the nominal relative clause.

The adnominal relative clause

(also relative clause, noun clause). This clause modifies a noun as in: (the book) that I have just read. It may be introduced by a RELATIVE PRONOUN such as who, which, that, or by a phrase containing a relative pronoun, such as for which, to whom, in the presence of whom, or by a relative adverb, such as where, when: (the hotel) where he stayed. Under certain circumstances, the relative pronoun may be omitted: (the music) she composed; (the safe) I put the money in. Adnominal relative clauses of the type (She told me the reason) that they gave are to be distinguished from the superficially similar appositive clause that also modifies a noun: (She told me the reason) that they left. The appositive clause is introduced by the conjunction that, which may sometimes be omitted: (the reason) they left. The difference between the two types of clause is that the appositive clause is complete in itself (they left, not they left the reason), whereas the relative clause requires the relative item to be present or to be understood, since it functions in the clause (they gave that, meaning they gave the reason). The relationship between a noun and its appositive clause differs from that between a noun and its relative clause in that it may be expressed by inserting the verb be between the two: The reason is that they left. Furthermore, the nouns that are modified by an appositive clause are restricted to a small set of general abstract nouns such as fact, idea, news, report.

Restrictive and non-restrictive clauses

The two major types of adnominal relative clauses are restrictive relative clauses and non-restrictive relative clauses. A restrictive relative clause (also defining relative clause) is a relative clause with the semantic function of defining more closely what the noun modified by the clause is referring to. In the sentence My uncle who lives in Brazil is coming to see us, the relative clause who lives in Brazil restricts the reference of my uncle. The restrictive modification would distinguish this uncle from any others who might have been included. A non-restrictive relative clause (also non-defining relative clause) adds information not needed for identifying what a modified noun is referring to. The sentence My uncle, who lives in Brazil, is coming to see us contains the non-restrictive relative clause who lives in Brazil. This clause provides information about the uncle, but his identity is presumed to be known and not to need further specification. Non-restrictive relative clauses are usually separated from the noun phrases they modify by parenthetical punctuation (usually COMMAS, but sometimes dashes or brackets). In speech, there may be a pause that serves the same function as the parenthesis.

The sentential relative clause

This clause does not modify a noun. It may refer back to part of a sentence (She exercises for an hour a day, which would bore me: that is, the exercising would bore the speaker), to a whole sentence (He kept on bragging about his success, which annoyed all of us: that is, the continual bragging about his success annoyed everybody), or occasionally to more than one sentence (I didn't enjoy the work. The weather was atrocious. I felt thoroughly homesick. And the locals were unpleasant. Which is why I have never been back there again). Which is the most common relative word to introduce a sentential relative clause, sometimes within a phrase (in which case, as a result of which), but other relative expressions with this type of clause include whereon, whereupon, from when, by when.

Nominal relative clauses

In the adnominal and sentential relative clauses, the relative word has as antecedent, a word or longer unit to which the relative word refers back: in the game which they were playing, the antecedent of which is the game, since in its clause which substitutes for the game (they were playing the game). The relative word in the nominal relative clause has no antecedent, since the antecedent is fused with the relative: I found what (that which; the thing that) you were looking for; He says whatever (anything that) he likes. Because they are free of antecedents, such clauses are sometimes called independent or free relative clauses. See ADJECTIVE CLAUSE.