From Proto-Tai *rɯːwᶜ (“to know”). Cognate with Thai รู้ (rúu), Northern Thai ᩁᩪ᩶, Isan ฮู้, Lao ຮູ້ (hū), Lü ᦣᦴᧉ (huu2), Shan ႁူႉ (hṵ̂u), Ahom 𑜍𑜥 (ruu) or 𑜍𑜤𑜈𑜫 (ruw), Zhuang rox, Saek รอ.
ꪭꪴ꫁ ('hụ)