What is the meaning of Grass_snake?

A nonvenomous snake of species Natrix natrix, native to Europe, with a yellow collar.

A snake of either of the two species of the nonvenomous green snake, Opheodrys, of North America:

  1. A smooth green snake (Opheodrys vernalis)
  2. A rough green snake (Opheodrys aestivus)

A smooth green snake (Opheodrys vernalis)

A rough green snake (Opheodrys aestivus)

Source: wiktionary.org