attclause

Attclause, short for attributive clause, is a type of dependent clause that modifies a noun. In many linguistic traditions, attributive clauses are equivalent to relative clauses, though some grammars distinguish finer subtypes. The main function of an attclause is to limit, identify, or describe the head noun by providing additional information.

Syntactic position and form vary by language. In English, attributive clauses typically follow the noun they modify, as in the restrictive example "the book that I bought" or the non-restrictive example "My bike, which I restored, runs well." They are usually introduced by relative pronouns such as who, which, or that, though a reduced or zero-relative form is possible, as in "the person I met." Prepositions can be stranded or pied-piped within the clause, depending on the language.

Types and distinctions often noted by grammars include restrictive (defining) versus non-restrictive (non-defining) attclause. Restrictive clauses specify which entity is being referred to and are not set off by commas; non-restrictive clauses add incidental information and are set off by commas. Some languages place attributive clauses before the noun, while English generally uses post-nominal placement. In others, such as Japanese, the clause precedes the noun as a prenominal modifier without a relative pronoun.

Cross-linguistic variation is common: some languages favor adjectives or participial phrases as modifiers instead of clausal relatives; others rely on case, mood, or particles to mark the attclause. In computational linguistics and corpora, the label attclause is sometimes used in annotation schemes to identify attributive relative clauses within noun phrases.