From Proto-Tai *ɣamᴮ (“night”). Cognate with Thai ค่ำ (kâm), Northern Thai ᨤᩴ᩵ᩣ, Lao ຄ່ຳ (kham), Lü ᦆᧄᧈ (xam¹), Shan ၶမ်ႈ (khām), Ahom 𑜁𑜪 (khaṃ), Saek กฺั้ม.
haemh (1957–1982 spelling həmƅ)