H. W. Fowler established a terminology (I do not know if it originates with him), where clauses that are related to another clause through a pronoun are called relative clauses; he further drew a distinction between restrictive and non-restrictive relative clauses to explain his famous rule about when to apply that vs. which.
The Cambridge Grammar of the English Language rejects this terminology in favour of another terminology:
- Instead of restrictive relative clause, the CGEL prefers integrated relative clause;
- Instead of non-restrictive relative clause, the CGEL (always?, usually?) prefers supplementary relative clause.
Why does the CGEL, reflecting the preference in Anglistics, follow this alternative terminology?