From Proto-Tai *lɯ:kᴰ (“child”). Cognate with Thai ลูก (lûuk), Northern Thai ᩃᩪᨠ, Lao ລູກ (lūk), Lü ᦟᦴᧅ (luuk), Tai Dam ꪩꪴꪀ, Shan လုၵ်ႈ (lūk), Zhuang lwg.
ᥘᥧᥐ (luk) (old orthography ᥘᥧᥐ)