also: たいよう
noun
Only with reading だいよう
Rare euphemistic term for feces, literally 'big business'; compare 大便 (だいべん). Restricted to reading だいよう.
See also: 大便
古い文献では「大用」を排泄物の婉曲表現として使うことがある。
In old texts, 大用 is sometimes used as a euphemism for excrement.
noun
large effect; great use
Rare term for a significant effect or important purpose; not in common modern use.
この薬は大用があると古文書に記されている。
This medicine is recorded in old documents as having great effect.
Compound of 大 (big) and 用 (business/use). The 'feces' sense is a euphemism paralleling 大便 (big convenience), while the 'large effect' sense is a literal reading of the kanji.