From Proto-Kra, from Proto-Kra-Dai. Cognate with A'ou [Bigong] (ɭe³¹)zai³³, Proto-Be *ȵumᴬ¹ (whence nɔm¹ ~ nam¹ ~ nɐm¹ ~ num¹ ~ ȵum¹ ~ ʑum¹ across different lects) and Proto-Hlai *hjɯːm (whence zɯːm¹ ~ zɯːm⁴ ~ zuːm⁴ across different lects) .
ðam³²²