English
floatboard
From float + board.
Proto-Indo-European *plewd- ‘to float, swim, fly’
Proto-Germanic *flutōną ‘to float’
Proto-West Germanic *flotōn ‘to float’
Old English flotian ‘to float’
Middle English floten ‘to float’
English float
Proto-Germanic *burdą ‘board’
Proto-West Germanic *bord ‘board’
Old English bord ‘board’
Middle English boord
English board
Today it means
noun A board on the rim of an undershot water wheel on which the water acts and moves the wheel.
Language periods are conventional ranges, not dates for this word.
Etymograph / floatboard