1. (Science: zoology) One of the several species of small rodents of the genus mus and allied genera, larger than mice, that infest houses, stores, and ships, especially the Norway, or brown, rat (M. Alexandrinus). These were introduced into Anerica from the old world.
It so chanced that, not long after the accession of the house of Hanover, some of the brown, that is the german or Norway, rats, were first brought over to this country (in some timber as is said); and being much stronger than the black, or, till then, the common, rats, they in many places quite extirpated the latter. The word (both the noun and the verb to rat) was first, as we have seen, leveled at the converts to the government of George the First, but has by degrees obtained a wide meaning, and come to be applied to any sudden and mercenary change in politics. bamboo rat, any American rat of the genus Neotoma, especially N. Floridana, common in the southern united states. Its feet and belly are white.
Origin: AS. Raet; akin to D. Rat, OHG. Rato, ratta, G. Ratte, ratze, OLG. Ratta, LG. & Dan. Rotte, Sw. Ratta, F. Rat, Ir. & Gael radan, Armor. 45c Raz, of unknown origin. Cf. Raccoon.