1530s, a back-formation from protraction and in part from Latin protractus, past participle of protrahere "to draw forth, prolong." Etymologically identical with portray, which was altered in French. Related: Protracted; protracting.
protostar
prototype
prototypical
Protozoa
protozoic
protract
protraction
protractor
protrude
protrusion
protuberance