In grammar, a complement is a word, phrase, or clause that is necessary to complete the meaning of a given expression.
The Cambridge Grammar of the English Language[5] assigns the term "predicative complement" to both uses and shifts the terminological distinction to the verb: In many modern grammars (for instance in those that build on the X-bar framework), the object argument of a verbal predicate is called a complement.
A more detailed definition of the adjunct emphasizes its attribute as a modifying form, word, or phrase that depends on another form, word, or phrase, being an element of clause structure with adverbial function.
The terminology used to denote arguments and adjuncts can vary depending on the theory at hand.
Some dependency grammars, for instance, employ the term circonstant (instead of adjunct) and follow Tesnière (1959).