The obligatory element in a phrase: it may be preceded or followed by a modifier. The head is the essential item. So for noun phrases, there must be a noun, but it can be modified by an adjective: stench / foul stench / really foul stench - or by a clause: the stench I noticed last night.

the central or most important element in a construction which determines the external distribution of the construction and places certain requirements on the words or constituents it occurs with. For example, the verb saw is head of the sentence The big man saw Mary and of the VP saw Mary. Nouns are heads of NPs, prepositions are heads of PPs, adjectives of APs, etc. In lexicography, head is another term for headword.

the central element of a phrase which governs the other parts of the phrase or sentence.

The head of a lexical phrase is a lexical head around which the phrase is built, i.e. Noun Phrases like a good CD have a head Noun such as CD. The head of a functional phrase may be an inflection such as ‘-s' or a grammatical word such as the.

The main element in a phrase, on which other elements depend. The noun phrase los otros problemas acuciantes has the noun problemas as its head.

The term head has three different meanings in syntactic theory. First, in the theory of phrase structure, the term refers to the syntactic and semantic core of a phrase. In X' theory, the particular theory of phrase structure developed in this book, a head projects an intermediate and maximal projection, along with optional arguments. Second, the head of a movement chain is simply the highest element in the chain. In the case of verb movement, the head in the chain sense happens to be a head in the X' sense. But when a maximal projection moves, the head of the chain is a maximal projection. Third, the term head can refer to the noun that is modified by a relative clause. Given our analysis of relative clauses as involving wh- movement, and hence a chain (see Chapter 9), this usage is potentially especially confusing. In the relative clauses in (i), the head of the relative clause in this third sense is italicized, whereas the head of the chain formed by movement of the relative clause is underlined. the book [CP [DP which ]i I am reading ti ] the author [CP [DP whose book ]i I like ti best

A head is a morpheme or base to which an affix is adjoined. A synonym for root.

In linguistics, the head is the morpheme that determines the category of a compound or the word that determines the syntactic type of the phrase of which it is a member.