This paper proposes the following definitions of commonly used terms: – clause: A clause is a combination of a predicate (full verb or nonverbal predicate) and its arguments, plus modifiers. – sentence: A sentence is a maximal clause, i.e. a clause that is not part of another clause. – complex clause (= “complex sentence”): A complex clause is a clause that contains at least one other clause – subordinate (= embedded) clause: A subordinate/embedded clause is a clause that is an argument (“complement clause”), and adnominal modi- fier (“relative clause”), or an adverbial modifier (“adverbial clause”) (but see Haspelmath 1995). – matrix clause (of subordinate clause S): The matrix clause of subordinate clause S is the minimal clause that contains it. – matrix-clause fragment: A matrix-clause fragment is the part of a matrix clause that is not the subordinate clause. – main clause: A main clause is a clause that is not a subordinate clause.