Where does the word idiom originate?

The word "idiom" comes from Ancient Greek, specifically from the word ἴδιος (idios), meaning "one's own" or "peculiar".

This makes sense when you consider that idioms are expressions that have a meaning that is different from the literal meaning of the words used. They are, in a way, "peculiar" to a specific language or culture.

The word "idiom" was first used in English in the 16th century to refer to a style of writing or speech. It later evolved to its current meaning, referring to a phrase or expression that has a figurative meaning.