音頭
おんど lead (in a cheer, toast, song, etc.); (someone's) lead
Why it means this
音 (a tune) + 頭 (the lead) — leading off a song or cheer; 音頭を取る, to take the lead in organizing something; also a genre of folk dance songs (東京音頭).
Breakdown
Each character links to its full entry — origin story, stroke order, and readings.