2 Answers

A phrase is a small group of words that adds meaning to a word. A phrase is not a sentence because it is not a complete idea with a subject and a predicate.
In English there are five different kinds of phrases, one for each of the main parts of speech. In a phrase, the main word, or the word that is what the phrase is about, is called the head. In these examples, it is printed in bold. The other words in the phrase do the work of changing or modifying the head.
In a noun phrase, one or more words work together to give more information about a noun.
all my dear children
the information age
seventeen hungry lions in the rocks
In an adjective phrase, one or more words work together to give more information about an adjective.
so very sweet
earnest in her desire
very happy with his work
In a verb phrase, one or more words work together to give more meaning to a verb. In English, the verb phrase is very complex, but a good description of its many forms can be found here.
In an adverb phrase, one or more words work together to give more information about an adverb.
especially softly
formerly of the city of Perth
much too quickly to see clearly

In a prepositional phrase, one or more words work together to give information about time, location, or possession, or condition. The preposition always appears at the front of the phrase.
after a very long walk
behind the old building
for all the hungry children
in case it should happen again