A phrase does not include a verb. You can tell if a group of words is a phrase because it can always be replaced by a single word, eg the phrase ‘pet Siamese cat’ would be replaced by the single word ‘cat’ and still have the same basic meaning.

A single word phrase (SWP) is a phrase consisting of a single word. Although, on face value an oxymoron, in linguistics, single words can have similar properties to phrases, and it’s also frequently unclear what constitutes a word and what the boundaries are between word and phrase.