From Wiktionary, the free dictionary
Sino-Vietnamese word from 隊 (“troop; legion”) and 歌 (“song”), from Đội, perhaps modeled after Tiến quân ca.
Đội ca
- (formal or informal) the formal role title of Cùng nha ta đi lên (literally “Together We Rise”), the anthem of Đội; informally used as a shorter alternative title