Definition:
A syntactic construction in which one grammatical element (e.g., a noun) is accompanied (or modified) by another (e.g., an adjective). The accompanying element is called a modifier.
In morphology, modification is a process of change in a root or stem. See Examples and Observations, below.
See also:
Modifier
Attributive Noun
Compound Adjective
Dangling Modifier, Misplaced Modifier, and Squinting Modifier
Degree Modifier
Downtoner
Epithet
Intensifier
Predeterminer
Qualifier and Quantifier
Resumptive Modifier
Sentence Adverb
Stacking
Submodifier
Summative Modifier
Examples and Observations:
"Modifier contrasts with head. If a word or phrase in a construction is its head, it cannot simultaneously be a modifier in that construction. But, . . . an adjective, for example, may be a head of one phrase and simultaneously a modifier in a different phrase. In very hot soup, for example, hot is the head of the adjective phrase very hot (modified by very) and simultaneously the modifier of the noun soup."
(James R. Hurford, Grammar: A Student's Guide. Cambridge University Press, 1994)
Modifiers that appear before the head are called premodifiers. Modifiers that appear after the head are called postmodifiers.
Optional Syntactic Functions
"[Modification] is an 'optional' syntactic function accomplished within phrases and clauses. If an element is not required in order to complete the thought expressed by a phrase or clause, it is probably a modifier. You might think of modification as a 'macro-function' in that it covers a very wide range of possible semantic notions, from various kinds of adverbial functions to nominal modification (size, shape, color, value, etc.). . . .
"Complementation is distinct from modification in that modification is always 'optional' from a syntactic perspective . . .. Modifying elements have a much 'looser' syntactic association with their heads than complements do."
(Thomas E.