parenthetical expression
Linguistics term for a word, phrase, or clause inserted into a sentence as an aside, often marked by parentheses, commas, or dashes.
He continued talking, using parenthetical expressions.
The parenthetical expression in this sentence provides supplementary information.
Compound of 挿入 (insertion) + 句 (phrase/clause). The exact historical derivation is uncertain, but the term follows standard Sino-Japanese word formation patterns.