pilot snake
/ˈpʌɪlət sneɪk/US
noun
1The copperhead snake, Agkistrodon contortrix (family Viperidae), of North America.
2Either of two colubrid snakes, the pine snake (Pituophis melanoleucus) and the black racer (Coluber constrictor).
3Any of several rat snakes (genus Elaphe), specifically the black rat snake, E. obsoleta, a large constricting snake of eastern North America (also called pilot black-snake).
Origin
Late 18th century; earliest use found in Transactions of the American Philosophical Society. From pilot + snake. With sense 1 compare earlier pilot; on the origin of the name compare quot. 1890 at sense 1, and quot. 1782 at pilot.