mid-15c., "drawing or writing of numbers," from Middle French protraction (15c.) and directly from Late Latin protractionem (nominative protractio) "a drawing out or lengthening," noun of action from past participle stem of Latin protrahere "to draw forward, draw out, bring forth;" figuratively "bring to light, reveal, expose," from pro "forward" (see pro-) + trahere "to draw" (see tract (n.1)). Meaning "act of drawing out or prolonging" is from 1530s.
