1 rat | Definition of rat
Logo
Menu
dictionary thesaurus

rat

noun
\ ˈrat How to pronounce rat (audio) \

Definition of rat

 (Entry 1 of 2)

1a : any of numerous rodents (Rattus and related genera) differing from the related mice especially by considerably larger size
b : any of various similar rodents
2 : a contemptible person: such as
a : one who betrays or deserts friends or associates
b : scab sense 3b
c : informer sense 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

rat

verb
ratted; ratting

Definition of rat (Entry 2 of 2)

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
Other Words from rat Synonyms More Example Sentences Learn More about rat

Keep scrolling for more

Other Words from rat

Noun

ratlike \ ˈrat-​ˌlīk How to pronounce ratlike (audio) \ adjective

Examples of rat in a Sentence

Noun

 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.

Verb

 The teacher knows what we did, which means that somebody ratted.
See More

Recent Examples on the Web: Noun

 Hartland residents said garbage and manure left at one home attracted dozens of rats. — USA TODAY, "Rocket’s last blast, Alaska drought, million-dollar ham: News from around our 50 states," 23 Aug. 2019 Lipkin has found similar results in studies of rats and mice in New York City subways and apartment buildings. — Karen Weintraub, Scientific American, "Mind the Staph: London Is Crawling with Antibiotic-Resistant Microbes," 1 Aug. 2019 Jackson said the mold problems and some of the other issues have abated, but that the pest control efforts have had little follow-through, resulting in a resurgence of rats. — oregonlive.com, "Tenant organizer sues, says property manager threatened eviction for union activities," 25 June 2019 The mayor agreed and the Pied Piper used his pipe to play a special tune that helps get rid of the rats. — Tamara Fuentes, Seventeen, "Who is The Pied Piper and How Does He Connect to "The Society"?," 21 May 2019 Inside, police found the home was infested with rats, mice, maggots and insects, authorities said. — Sam Tabachnik, The Denver Post, "Second brother in Englewood child pornography case sentenced to decades in prison," 26 July 2019 The third season of Stranger Things brought us many things: a nostalgic trip back to '80s mall culture, Steve in a sailor suit, gross disintegrating rats, a heartbreaking (possible) loss, and some most excellent hair. — Abby Gardner, Glamour, "All the Hidden Messages in the Hairstyles on Stranger Things," 20 July 2019 Coates stopped feeding birds, which dropped seeds that attracted rats, raccoons and an occasional coyote. — Janet Eastman, oregonlive.com, "What to do about cougars in the neighborhood, skunks under the house, bats in the attic," 19 July 2019 Some studies have shown that many animals, including rats, chickens, and dogs, at least appear to exhibit signs of empathy. — Natasha Daly, National Geographic, "Goats can perceive each other’s emotions from their voices," 15 July 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'rat.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of rat

Noun

before the 12th century, in the meaning defined at sense 1a

Verb

1812, in the meaning defined at intransitive sense 1

History and Etymology for rat

Noun

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

Note: 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.

Keep scrolling for more

Keep scrolling for more

More Definitions for rat

rat

noun
How to pronounce rat (audio)

English Language Learners Definition of rat

 (Entry 1 of 2)

: a small animal that has a pointed nose and a long, thin tail
: a person who is not loyal or who cannot be trusted
: a person who is bad or cruel

rat

verb

English Language Learners Definition of rat (Entry 2 of 2)

informal : to tell someone in authority (such as the police) about something wrong that someone has done : to betray someone

See the full definition for rat in the English Language Learners Dictionary

WORD OF THE DAY

See Definitions and Examples

Get Word of the Day daily email!