We found 2 dictionaries that define the word phrase structures:

General (2 matching dictionaries)

1. phrase structures: Merriam-Webster
2. phrase structures: Collins English Dictionary

(Note: See phrase_structure as well.)

Definitions from WordNet (phrase structure) ▸ noun:  the grammatical arrangement of words in sentences ▸ Also see phrase_structure ▸ Words similar to phrase structures ▸ Usage examples for phrase structures ▸ Idioms related to phrase structures ▸ Wikipedia articles (New!) ▸ Words that often appear near phrase structures ▸ Rhymes of phrase structures ▸ Invented words related to phrase structures