General terms:
* Idiom: This is the most direct term, but it's often used specifically for fixed expressions with figurative meanings.
* Expression: This is a broader term that encompasses idioms as well as other types of phrases with specific meanings.
* Phrase: This is the broadest term, referring to any sequence of words.
* Proverb: This specifically refers to a short, well-known saying that expresses a truth or piece of advice.
* Saying: This is a general term for any common expression, including idioms, proverbs, and other types of phrases.
* Collocation: This refers to words that often occur together, even if they don't have a figurative meaning.
* Turn of phrase: This refers to a distinctive way of expressing something, often used to describe idioms or poetic language.
* Cliché: This refers to an overused expression that has lost its original impact.
More specific terms:
* Metaphor: This refers to a figure of speech that compares two things without using "like" or "as."
* Simile: This refers to a figure of speech that compares two things using "like" or "as."
* Personification: This refers to a figure of speech that gives human qualities to inanimate objects or abstract concepts.
* Hyperbole: This refers to an exaggeration for effect.
* Understatement: This refers to a statement that downplays the importance of something.
* Euphemism: This refers to a polite way of expressing something that might be considered offensive or unpleasant.
The best word to use will depend on the specific context and the type of idiom or expression you are describing.
For example, you might use "idiom" to describe the phrase "kick the bucket," but you might use "expression" to describe the phrase "once in a blue moon," which is more of a common saying than a fixed idiom.
Do you have any specific examples in mind? I can help you choose the best word to describe them.