-tə(r) noun
( -s )
Etymology: Medieval Latin, from Latin protractus (past participle of protrahere to protract) + -or
1. : one that protracts: as
a. obsolete : one that prolongs : retarder , delayer
b. : a muscle that extends a part — opposed to retractor
2.
a. : an instrument made for laying down and measuring angles on paper and used in drawing and plotting
b. : a similar instrument for locating distant forest fires