Racer
late Old English, from Old Norse rás ‘current’. It was originally a northern English word with the sense ‘rapid forward movement’, which gave rise to the senses ‘contest of speed’ (early 16th century) and ‘channel, path’ (i.e. the space traversed). The verb dates from the late 15th century.
wiktionary
race + -er
etymonline
racer (n.)
"one who or that which races," 1640s of persons, 1660s of horses, 1793 of vehicles, by 1809 in American English in reference to a type of snake; agent nouns from race (v.).
WHEN a lad, I lived with my father in the then province of New Jersey, where the black snake, with a white throat, commonly called the racer, as well as the rattle snake, and other serpents, are frequently met with ; and I never remember to have heard any one dispute the power of charming belonging to several species of serpents, but more common to the black snake, called the racer, which I have twice seen in the operation. ["Extract from a letter from Samuel Beach, dated Whiting, July 24, 1795," in appendix to Samuel Williams, "The Natural and Civil History of Vermont," 2nd ed., 1809]
