Phrase

In grammar, a phrase (Greek φράση, sentence, expression, see also strophe) is a group of words that functions as a single unit in the syntax of a sentence.

For example the house at the end of the street (example 1) is a phrase. It acts like a noun. It contains the phrase at the end of the street (example 2), which acts like an adjective. Example 2 could be replaced by white, to make the phrase the white house. Examples 1 and 2 contain the phrase the end of the street (example 3) which acts like a noun. It could be replaced by the cross-roads to give the house at the cross-roads.

Most phrases have a head or central word which defines the type of phrase. In English the head is often the first word of the phrase. Some phrases, however, can be headless. For example, the rich is a noun phrase composed of a determiner and an adjective, but no noun.

Phrases may be classified by the type of head they take

Prepositional phrase (PP) with a preposition as head (e.g. in love, over the rainbow). Languages that use postpositions instead have postpositional phrases. The two types are sometimes commonly referred to as adpositional phrases.
Noun phrase (NP) with a noun as head (e.g. the black cat, a cat on the mat)
Verb phrase (VP) with a verb as head (e.g. eat cheese, jump up and down)
Adjectival phrase with an adjective as head (e.g. full of toys)
Adverbial phrase with adverb as head (e.g. very carefully)