Sino-Vietnamese word from 恐龍, composed of 恐 (“terror”) and 龍 (“dragon”), from Chinese 恐龍／恐龙 (kǒnglóng) or directly from Japanese 恐竜 (kyōryū). For the extended sense, semantic loan from Chinese 龍／龙 (long) or semantic loan from Japanese 竜 (ryū).
It is unclear when this term was adopted. In Địa cầu vạn vật luận - Động vật (1920), written by a French bishop, the term thú long was used to refer to "fossilized terrestrial crocodiles" such as mégalosaure, brontosaure, iguanodon.
- (Hà Nội) IPA(key): [xʊwŋ͡m˧˩ lawŋ͡m˧˧]
- (Huế) IPA(key): [kʰʊwŋ͡m˧˨ lawŋ͡m˧˧] ~ [xʊwŋ͡m˧˨ lɔŋ˧˧]
- (Hồ Chí Minh City) IPA(key): [kʰʊwŋ͡m˨˩˦ lawŋ͡m˧˧] ~ [xʊwŋ͡m˨˩˦ lawŋ͡m˧˧]