somnolence (n.)youdaoicibaDictYouDict[somnolence 词源字典]
late 14c., from Old French sompnolence (14c.), from Latin somnolentia "sleepiness," from somnolentus, from somnus "sleep" (see somnus). Related: Somnolency.[somnolence etymology, somnolence origin, 英语词源]