Oddly enough, the word counterpane started life as counterpoint.
This was not the musical term of the same spelling derived from Latin contra punctus relating to combined harmonies, but a corruption of an Old French term which was itself corrupted from Latin culcita puncta, meaning “a quilt.”
As the early heavy quilt began to give way to a lighter and ornamental outer bedcover in the seventeenth century, the second element, point, was gradually replaced by pane (French pan, “cloth”), long previously in use for “coverlet.”