cheering song; supporters' song; fight song
A song sung to cheer on a team, player, or group, commonly at sports events, school competitions, or political rallies.
野球の試合で、みんなで応援歌を歌った。
We all sang the cheering song at the baseball game.
He still remembers his alma mater's fight song.
Compound of 応援 (ouen, 'support, cheering') and 歌 (ka, 'song').