The Collaborative International Dictionary
Counter-tenor clef
Counter tenor \Coun"ter ten`or\ (t?n`?r). [OF. contreteneur. Cf. Contratenor, and see Tenor a part in music.] (Mus.) One of the middle parts in music, between the tenor and the treble; high tenor.
Counter-tenor clef (Mus.), the C clef when placed on the third line; -- also called alto clef.