non-restrictive relative clause - definition and synonyms

noun [countable] linguistics  /nɒn rɪˌstrɪktɪv relətɪv ˈklɔːz/
singularnon-restrictive relative clause
pluralnon-restrictive relative clauses
  1. a relative clause that gives extra information about a person, thing, or situation in the previous clause. There is usually a comma before the relative pronoun, indicating that the information in the relative clause is not essential. For example, in the sentence ‘None of the documents had a date, which was very confusing’, ‘which was very confusing’ is a non-restrictive relative clause.