ETYM Old Fren. descant, deschant, French déchant, discant, Late Lat. discantus, from Latin dis + cantus singing, melody, from canere to sing. Related to Chant, Descant, Discant.
A decorative accompaniment (often improvised) added above a basic melody; SYN. discant.
Music, simple counterpoint sung by trebles above melody; counterpoint; treble.
In music, a high-pitched line for one or more sopranos, added above the normal soprano line (melody) of a hymn tune; a high-pitched instrument of a family, such as the descant recorder (US soprano recorder); also, an improvised melody sung against a written voice part (see discant).

1. To sing in descant.
2. To talk at great length about something of one's interest.