Definition of rat
1a : any of numerous rodents (Rattus and related genera) differing from the related mice especially by considerably larger sizeb : any of various similar rodents
2 : a contemptible person: such asa : one who betrays or deserts friends or associatesb : scab 3bc : informer 2
3 : a pad over which a woman's hair is arranged
4 : a person who spends much time in a specified place a mall rat
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Examples of rat in a Sentence
a dirty old building infested by rats and mice
I can't believe that rat turned us in to the police!
No one understands why she's with a rat like him.
Every night he goes to work out with the other gym rats.
Origin and Etymology of rat
Middle English rat, ratte, going back to Old English ræt (attested once), akin to Old Saxon ratta “rat,” Middle Dutch ratte, rotte, Old High German ratta, radda, ratza (feminine weak nouns), also Old High German rato (masculine weak noun), probably going back to an ablauting paradigm *raþō (nominative), *rattaz/*ruttaz (genitive), *radeni/*rudeni (dative), going back to earlier *(H)rót-ōn, *(H)rt-n-ós, *(H)rt-én-i, of uncertain origin ◆The origin of the etymon beyond Germanic is obscure. Regionally in German Ratz or Ratze are applied to other animals (as the dormouse and the polecat); if these senses are old, the application of the etymon to rats (Rattus rattus, Rattus norvegicus) may be secondary. Note that if the base is pre-Germanic *rat-, there is no connection to either Latin rōdere “gnaw, nibble, eat away” (see rodent) or rādere “scrape, shave” (see rase), as has often been assumed.
rat
Definition of rat
ratted
;ratting
intransitive verb
1 : to betray, desert, or inform on one's associates —usually used with on
2 : to catch or hunt rats
3 : to work as a scab
transitive verb
1 : to give (hair) the effect of greater quantity (as by use of a rat)
2 : to inform on : turn in —usually used with out ratted out his accomplice
Examples of rat in a Sentence
The teacher knows what we did, which means that somebody ratted.
First Known Use of rat
1812
RAT Defined for English Language Learners
rat
playDefinition of rat for English Language Learners
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: a small animal that has a pointed nose and a long, thin tail
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: a person who is not loyal or who cannot be trusted
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: a person who is bad or cruel
rat
Definition of rat for English Language Learners
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: to tell someone in authority (such as the police) about something wrong that someone has done : to betray someone ( US )
RAT Defined for Kids
Definition of rat for Students
1 : a gnawing animal with brown, black, white, or grayish fur that looks like but is larger than a mouse
2 : a person who betrays friends
Medical Dictionary
rat
playMedical Definition of rat
: any of the numerous rodents (family Muridae) of Rattus and related genera that differ from the murid mice by their usually considerably larger size and by features of the teeth and other structures and that include forms (as the brown rat, the black rat, and the roof rat) which live in and about human habitations and in ships, have become naturalized by commerce in most parts of the world, and are destructive pests consuming or destroying vast quantities of food and other goods and acting as vectors of various diseases (as bubonic plague)
Learn More about rat
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See words that rhyme with rat Thesaurus: All synonyms and antonyms for rat Spanish Central: Translation of rat Nglish: Translation of rat for Spanish speakers Britannica English: Translation of rat for Arabic speakers Britannica.com: Encyclopedia article about rat
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