(common “Jōyō” kanji)
*/moko/ → *⟨muko1⟩ → */mukʷo/*⟨mo(1)ko1⟩ → */mʷokʷo/ → /muko/
Found in the Nihon Shoki of 720 CE with the ideographic spelling 聟.
Although the reading muko is not confirmed in Old Japanese documents, the presence of cognate words suggests that this may be from Proto-Japonic *moko (cognate with Okinawan 婿 (mūku), Kunigami 婿 (mufu), Miyako 婿 (muku) and the moko below). This would be the a result of a phonological change, whereby non-final */o/ in Proto-Japonic nouns shifted to become /u/ in Central Old Japanese.
In regard to the derivation, there are some theories proposed, however many of them are associated with the verbs 向かう (mukau, “to go towards”) and 迎える (mukaeru, “to receive”), both derived from 向く (muku, “to turn toward”), from Proto-Japonic *muk-, from the idea of "the facing party, the other person (of a pair)"; see also 向こう (mukō, “the other side, the facing side”). Theories to explain this inconsistency in the proto-forms have not been published yet.
婿 • (muko)
- a husband who has entered his wife's house
- a son-in-law
- Synonyms: 女婿 (josei), 娘婿 (musumemuko)
- a groom, bridegroom (man who is about to get married)
- Synonyms: 新郎 (shinrō), 花婿 (hanamuko)
- (all senses): 嫁 (yome)
*/moko/ → ⟨mo(1)ko1⟩ → */mʷokʷo/ → /moko/
From other Old Japanese dialects besides Central Old Japanese, with a conserved */o/ as ⟨o1⟩.
Possibly cognate or otherwise related with Old Japanese もこ (mo1ko1, “companion, fellow”).
婿 • (moko)
- (dialectal, Tōhoku, Northern Kantō, Niigata, Nagano, Chūgoku, etc.) Nonstandard form of むこ (muko) above
From Middle Chinese 婿 (MC sejH).
婿 • (sei)
- ^ Frellesvig, B. & Whitman, J. (2008) "The Vowels of Proto-Japanese", Proto-Japanese: Issues and Prospects. Amsterdam: John Benjamins Pub. Co.
- ^ 1988, 国語大辞典（新装版） (Kokugo Dai Jiten, Revised Edition) (in Japanese), Tōkyō: Shogakukan
- ^ 2006, 大辞林 (Daijirin), Third Edition (in Japanese), Tōkyō: Sanseidō, →ISBN