From Proto-Southwestern Tai *suːᴬ¹ (“you (plural)”). Cognate with Thai สู (sǔu), Northern Thai ᩈᩪ (sǔu), Isan สู, Lao ສູ (sū), Lü ᦉᦴ (ṡuu), Tai Dam ꪎꪴ, Shan သူ (sǔu), Ahom 𑜏𑜥 (sū), Zhuang sou.
ᥔᥧᥴ (sú) (1963 orthography ᥔᥧ́)