grass snake

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of several greenish nonvenomous snakes, especially Opheodrys vernalis of eastern North America or Natrix natrix of Europe.

Century Dictionary and Cyclopedia

1. n. Same as ringed snake (which see, under snake).
2. n. In the United States, the green-snake.

Wiktionary

1. n. A nonvenomous snake, Natrix natrix, native to Europe, with a yellow collar.
2. n. A greenish nonvenomous snake, Opheodrys vernalis, of North America.

GNU Webster's 1913

1. n. (Zoöl.) The common green snake of the Northern United States. See Green snake, under Green.

WordNet 3.0

1. n. any of numerous nonvenomous longitudinally-striped viviparous North American and Central American snakes
2. n. harmless European snake with a bright yellow collar; common in England
3. n. either of two North American chiefly insectivorous snakes that are green in color