Origin: 1400–50; late ME
ertheworm. See earth, worm 
Regional variation note:
The earthworm, a commonly used bait for angling, is also called an angleworm in the Northern U.S. and a fishworm in the Northern and Midland U.S. and in New England. It is called a fishing worm in parts of the Midland and Southern U.S., and a wiggler in the Southern U.S.
Because the worm often comes to the surface of the earth when the ground is cool or wet, it is also called a nightwalker in New England, a nightcrawler, chiefly in the Northern, North Midland, and Western U.S., and a dew worm, chiefly in the Inland North and Canada. It is also called a red worm in the North Central, South Midland, and Southern U.S.
[urth-wurm] 