elaboration; amplification; explication
Rare, formal noun meaning the act of expanding on or explaining something in detail. Not in common everyday use.
In this paper, I attempted an elaboration of that concept.
The word 衍義 is composed of 衍 (overflow, extend) and 義 (meaning, righteousness). It likely originated in classical Chinese texts to denote the extension or elaboration of meaning. The exact historical derivation is uncertain.