English Help: what's this called?

Factual Questions
1

What is the term for a phrase like “I’m looking for a needle in a haystack” or “I’m spinning my wheels”?

It’s not a euphemism, alliteration, idiom, colloquialism or any of the other flood of words that came rushing back to me.

It’s on the tip of my tongue, but I need a little help.

E3

2

Aphorism?

3

Metaphor?

4

Many would just call those expressions or figures of speech.

5

Giles has it. Yes, it’s a figure of speech, but it’s a metaphor.

Thanks,

I knew it was something simple like that!

My brain is still on vacation I guess.

E3

6

Or colloquialisms.