subordinate clause
noun [ C ] language specialized uk/səˌbɔː.dɪ.nət ˈklɔːz/ us/səˌbɔːr.dɪ.nət ˈklɑːz/
从句，从属分句
in grammar, a clause that cannot form a sentence on its own but can be joined to a main clause to form a sentence
Synonym: dependent clause