English
flutterboard
From flutter + board.
Proto-Indo-European *plewd- ‘to float, swim, fly’
…
Proto-Germanic *flutōną ‘to float’
Proto-Germanic *flutrōną
Old English floterian ‘to float about, flutter’
Middle English floteren ‘to be held up or be supported by water’
English flutter
Proto-Germanic *burdą ‘board’
Proto-West Germanic *bord ‘board’
Old English bord ‘board’
Middle English boord
English board
Today it means
noun A buoyancy board made of foam, used to support the body when in water.
Language periods are conventional ranges, not dates for this word.
Etymograph / flutterboard