Deschant

Part of speech: verb, noun

Definitions

1. An upper melodic line added above a plainchant or hymn tune ; to sing or improvise such a line over a melody ; to comment or discourse at great length on a subject
2. A higher counter-melody sung over a plain tune ; to perform that overlying melody while singing ; to hold forth at length on some topic
3. The added upper voice set above a basic musical theme ; to chant a melody over an existing tune ; to expound or dwell lengthily on a particular matter

Etymology: The word began as a term for singing in parts. Medieval Latin "discantus" combined "dis-", meaning apart, with "cantus", meaning song, and named the practice of adding a second voice above a plainchant melody, moving in counterpoint to it. Old French "deschant" carried this musical sense into English. From music, the term drifted into speech. To descant upon a subject came to mean discoursing on it at length, with elaboration and variation, much as a musician embroiders a tune. The verb keeps that figurative sense, while the noun still names a high accompanying line in choral and recorder music.