カバー曲[kabaakyoku] remake of another artist's song (a "cover")
サイン曲線[sainkyokusen] sinusoid
愛唱曲[aishoukyoku] favourite song
委曲[ikyoku] details
一曲[ikkyoku] tune (melody, piece of music)

迂曲[ukyoku] meander
円曲[enkyoku] roundabout way (of speaking or working)
円錐曲線[ensuikyokusen] conic curve
円舞曲[enbukyoku] waltz (composition)
演曲[enkyoku] musical program

哀歌[aika] lament (song)
愛唱歌[aishouka] (one's) favourite song
詠歌[eika] poem (esp. tanka)
艶歌[enka] enka
応援歌[ouenka] rooters' song

歌い合う[utaiau] to sing responsively
歌い上げる[utaiageru] to sing at the top of one's voice
歌詠み[utayomi] tanka composer
歌会[utakai] poetry party or competition

歌謡[kayou] song
歌謡曲[kayoukyoku] popular song
神謡集[shinyoushuu] collection of mythology
俗謡[zokuyou] popular song
童謡[douyou] children's song

民謡[minyou] folk song
謡い[utai] noh chanting
謡曲[youkyoku] noh song
俚謡[riyou] ballad
謡う[utau] to sing