thallus (n.)youdaoicibaDictYouDict[thallus 词源字典]
1829, Latin, from Greek thallos "green shoot, young branch, twig," related to thalia "abundance," thalos "scion, child," ultimately from PIE root *dhal- "to bloom" (cognates: Armenian dalar "green, fresh," Albanian dal' "I sprout," Old Irish duilesc, a type of algae).[thallus etymology, thallus origin, 英语词源]