A phrase is a group of related words that lacks both a subject and a verb. Because it lacks a subject and a predicate it cannot act as a sentence.
A phrase typically functions as a single part of speech in a sentence (e.g., noun, adjective, adverb).
There are four types of phrases:
1. Prepositional phrases, which begin with a preposition and include the object of the preposition.
2. Participial phrases, which begin with the participle and include the object of the participle or other words that are connected to the noun by the participle.
3. Gerund phrases, which begin with the gerund and include the object of the gerund or other words that are acting as the complete subject or complete object.
5. Appositives, not every appositive is a phrase and not every phrase is an appositive. For the record, an appositive is a word, phrase or clause that means the same thing as (i.e., synonym) or further explains another noun (pronoun).