“clause: A part of a sentence whose structure is itself like that of a sentence. Thus, in particular, one which includes a verb and elements that can and must accompany it.
In older treatments one clause was described as following another; e.g. in I said I saw her a main clause I said would be followed by a subordinate clause I saw her. As now defined, the main clause is the sentence as a whole and the subordinate clause is said to be included in it: thus, with brackets around each, [I said [I saw her]]. Clauses are distinguished in most accounts from phrases, by criteria which may vary, however, from one to another.”
Excerpted from: Matthews, P.H., ed. The Oxford Concise Dictionary of Linguistics. New York: Oxford University Press, 2014.
Mark's Text Terminal 