A subordinating conjunction is a word such as 'although', 'because', or 'when' which begins a subordinate clause. Compare co-ordinating conjunction.
[technical]
English Easy Learning GrammarSubordinationWhen two or more clauses are joined by a conjunction other than and, but, or, or yet,one of the clauses is the main clause; the other clauses are subordinate ... Read more
English Easy Learning GrammarSentences and clausesA clause is a group of words which contains a verb. The verb in a clause can be finite Use this pan for the pasta. He missed the turnoff. or non-finite. To ... Read more
subordinating conjunction in British English
noun
a conjunction that introduces subordinate clauses, such as if, because, although, and until
Compare coordinating conjunction
subordinating conjunction in American English
a conjunction that connects subordinate words, phrases, or clauses to some other sentence element (Ex.: if, as, so, unless, although, when)