A
non-restrictive clause is a clause in which a noun phrase is used to avoid repetition (as the
referent of an
anaphor, meaning that it is substituted by another word but refers to the same noun) is determined by its
antecedent where the dependent is peripheral (non-essential) in the secondary constituent, as opposed to a
restrictive clause, where the dependent is central (essential) to its primary constituent. A non-restrictive clause does not identify the referent of its noun, but only provides information about it.