1. A phrase that acts like a sentence: This could refer to a sentence fragment, which is a group of words that lacks a subject or verb and doesn't express a complete thought. Examples:
* "Running down the street." (Missing a subject)
* "Because it was raining." (Missing a main verb)
2. A phrase within a sentence: This could refer to any phrase that functions as part of a sentence, such as a noun phrase, verb phrase, prepositional phrase, etc. For example:
* "The big red ball" (noun phrase)
* "Is rolling down the hill" (verb phrase)
* "Under the table" (prepositional phrase)
3. A short, informal sentence: This could be a phrase that functions grammatically as a complete sentence but is expressed in a shortened, informal way. Example:
* "See you later." (Instead of "I will see you later.")
If you can provide more context about where you encountered this term, I might be able to give you a more specific answer.