Meaning of field rat in English:

field rat

noun

  • (Originally) any of various rodents that frequent cultivated land, including voles (genus Microtus) and the brown rat, Rattus norvegicus; especially (in later use) any of several Asian and Australasian rats of the genus Rattus.

Origin

Early 17th century; earliest use found in Pierre Erondelle (fl. 1586–1609).