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.
