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

課す[kasu] to levy
課する[kasuru] to levy
課員[kain] section staff
課外[kagai] extracurricular
課業[kagyou] schoolwork

課金[kakin] charges
課制[kasei] section system (companies)
課税[kazei] taxation
課税控除[kazeikoujo] tax exemption

飲み放題[nomihoudai] all you can drink
演習問題[enshuumondai] practice problem
演題[endai] subject of an address
応用問題[ouyoumondai] application problem
歌題[kadai] name of poem

課題[kadai] subject
画題[gadai] motif
解題[kaidai] synopsis
改題[kaidai] changing a title
外交問題[gaikoumondai] diplomatic issue