The dependent of an expression consisting of a °noun and its °modifiers is the modifier; the dependents of an expression consisting of a °verb and its °arguments and °adjuncts are the arguments and adjuncts; and the dependent of an expression consisting of an °adjective and its °degree qualifiers is the degree qualifier.
Basically, the dependent constituents in a construction are those constituents that are not the head. The term was introduced by Nichols (1986), who was inspired by the dependency grammar tradition (Tesnière 1959; Hays 1964; and subsequent work).
dependent (CXN) = any element of a construction that is not the head. Example: in the phrase an ancient watch, ancient and an are dependents. (Section 2.2.1)