Rat - Definition - Law Dictionary Home Dictionary Definition rat

Definition :

One of several species of small rodents of the genus Rattus formerly included in Mus and allied genera of the family Muridae distinguished from mice primarily by being larger They infest houses stores and ships especially the Norway rat also called brown rat Rattus norvegicus formerly Mus decumanus the black rat Rattus rattus formerly Mus rattus and the roof rat formerly Mus Alexandrinus now included in Rattus rattus These were introduced into America from the Old World The white rat used most commonly in laboratories is primarily a strain derived from Rattus rattus