Simile
Etymology
From Latin simile, the neuter of similis, "like, resembling" — literally "a like thing." Where the related word "similar" stayed an adjective, English borrowed the neuter noun to name the figure of speech itself: a stated resemblance rather than a claimed identity.
noun · /SIM-uh-lee/
A comparison of two unlike things made explicit with a word such as "like" or "as."
What it names
The open comparison — "sharp as a tack," "cried like a baby" — that flags itself as a comparison, keeping the two things side by side rather than collapsing them.
Example
Her best simile stuck with me for days: the deadline loomed "like a wave you can see but can’t outrun."
Related idea
Metaphor drops the "like" and asserts the two things are one; a simile keeps the comparison visible, which makes it gentler and more precise but less bold.