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).
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