four-character compound word; four-character idiom
Refers to a set phrase or idiom consisting of four kanji characters, often derived from classical Chinese. Many are idiomatic, but the term can also include non-idiomatic four-character compounds.
"Ichi-go ichi-e" is a famous four-character idiom.
Please look up the meaning of this four-character compound.
四字熟語 is specifically a four-character idiomatic compound, while 慣用句 covers idiomatic phrases of any length or structure.
Standard kanji spelling.
Variant using Arabic numeral 4; less common but seen in informal contexts.
Compound of 四字 (four characters) + 熟語 (compound word, idiom). The term itself is a modern classification for traditional four-character phrases.