בלאַנק

ETYMOLOGY

ON blakkr 'black, dun-colored', Dutch blank 'white, transparent; inundated', OHG blanc 'shining, white', NHG blank 'shiny, sheer'; from PGmc ✱blanka- 'colorless (?)' (DRV); adjective created to the verb ✱blinkan- (Dutch blinken 'to shine')
The Germanic adjective spread to Romance, French blanc, then back to English blank.