köken: Originally referred to a quick, turbulent section of a river. This latter meaning could come from the present participle of a hypothetical verb serlik, with rl assimilating into ll. The root ser is an onomatopoeia for fast movement or rotation and can be found in sarj, sarkall, sarkantyú, sarok, serdül, serény, serken, sőre, surján, sürget, sürög, sűrű and szorgalom.
köken: From Proto-Tai *ŋɯəkᴰ (“crocodile”); cognate with Lao ເງືອກ (ngư̄ak), Tai Dam ꪹꪉꪀ, Shan ငိူၵ်ႈ (ngōek), Tai Nüa ᥒᥫᥐ (ngoek), Ahom 𑜂𑜢𑜤𑜀𑜫 (ṅük), Nong Zhuang ngowg, Zuojiang Zhuang ngweg. According to Pittayaporn (2009-2010:16) from Middle Chinese 鱷 (MC ngak, “crocodile”), yet Vovin (2021:113) contends that the loan direction is from Tai to Eastern Han Chinese.