cá thu
Vietnamese
editEtymology
editThe second element is from a Tai language. Compare Thai ทู (tuu).
Curiously, the Pacific saury, also known as the mackerel pike, is called cá thu đao in Vietnamese, corresponding to 秋刀魚/秋刀鱼 (qiūdāoyú) (SV: thu đao ngư) in Chinese.
The thu elements in cá thu ("mackerel") and cá thu đao ("mackerel pike") are therefore seemingly unrelated, with the former being a Tai loan, while the latter is the Sino-Vietnamese reading of 秋 (qiū).