any of several long-tailed rodents of the family Muridae, of the genus Rattus and related genera, distinguished from the mouse by being larger.
2.
any of various similar or related animals.
3.
Slang. a scoundrel.
4.
Slang.
a.
a person who abandons or betrays his or her party or associates, esp. in a time of trouble.
b.
an informer.
c.
a scab laborer.
5.
Slang. a person who frequents a specified place: a mall rat; gym rats.
6.
a pad with tapered ends formerly used in women's hair styles to give the appearance of greater thickness.
–interjection
7.
rats, Slang. (an exclamation of disappointment, disgust, or disbelief.)
–verb (used without object)
8.
Slang.
a.
to desert one's party or associates, esp. in a time of trouble.
b.
to turn informer; squeal: He ratted on the gang, and the police arrested them.
c.
to work as a scab.
9.
to hunt or catch rats.
–verb (used with object)
10.
to dress (the hair) with or as if with a rat.
—Idiom
11.
smell a rat, to suspect or surmise treachery; have suspicion: After noting several discrepancies in his client's story, the attorney began to smell a rat.
[Origin: bef. 1000; ME rat(t)e, OE ræt; c. D rat, G Ratz, Ratte]
O.E. ræt. Similar words in Celtic (Gael. radan), Romance (It. ratto, Sp. rata, Fr. rat) and Gmc. (M.L.G. rotte, Ger. ratte) languages, but connection is uncertain and origin unknown. Perhaps from V.L. *rattus, but Weekley thinks this is of Gmc. origin, "the animal having come from the East with the race-migrations" and the word passing thence to the Romanic languages. American Heritage and Tucker connect O.E. ræt to L. rodere and thus PIE *red- "to scrape, scratch, gnaw," source of rodent (q.v.). Klein says there is no connection and suggests a possible cognate in Gk. rhine "file, rasp." Weekley connects them with a question mark and Barnhart writes, "the relationship to each other of the Germanic, Romance, and Celtic words for rat is uncertain." OED says "probable" the rat word spread from Germanic to Romance, but takes no position on ultimate origin. M.E. common form was ratton, from augmented O.Fr. form raton. Sense of "one who abandons his associates" (1629) is from belief that rats leave a ship about to sink or a house about to fall and led to meaning "traitor, informant" (1902; verb 1910). Interjection rats is Amer.Eng., 1886. To smell a rat is c.1550. Rat-race "competitive struggle" is 1939. Ratsbane (1523) is arsenic. Rat fink is teen slang from 1963. Rathole in fig. sense of "nasty, messy place" first attested 1812. _____-rat, "person who frequents _____" (in earliest ref. dock-rat) is from 1864. Rat-pack "juvenile gang" is from 1951.
any of various long-tailed rodents similar to but larger than a mouse
2.
someone who works (or provides workers) during a strike [syn: scab]
3.
a person who is deemed to be despicable or contemptible; "only a rotter would do that"; "kill the rat"; "throw the bum out"; "you cowardly little pukes!"; "the British call a contemptible person a 'git'"
4.
one who reveals confidential information in return for money [syn: informer]
5.
a pad (usually made of hair) worn as part of a woman's coiffure
verb
1.
desert one's party or group of friends, for example, for one's personal advantage
2.
employ scabs or strike breakers in
3.
take the place of work of someone on strike [syn: fink]
4.
give (hair) the appearance of being fuller by using a rat
5.
catch rats, especially with dogs
6.
give away information about somebody; "He told on his classmate who had cheated on the exam"
Rac*coon"\, n. [F. raton, prop., a little rat, fr. rat rat, perhaps of German origin. See Rat.] (Zo["o]l.) A North American nocturnal carnivore (Procyon lotor) allied to the bears, but much smaller, and having a long, full tail, banded with black and gray. Its body is gray, varied with black and white. Called also coon, and mapach. Raccoon dog (Zo["o]l.), the tanate. Raccoon fox (Zo["o]l.), the cacomixle.
Rat\, n. [AS. r[ae]t; akin to D. rat, OHG. rato, ratta, G. ratte, ratze, OLG. ratta, LG. & Dan. rotte, Sw. r[*a]tta, F. rat, Ir. & Gael radan, Armor. raz, of unknown origin. Cf. Raccoon.]1. (Zo["o]l.) 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. 2. A round and tapering mass of hair, or similar material, used by women to support the puffs and rolls of their natural hair. [Local, U.S.] 3. One who deserts his party or associates; hence, in the trades, one who works for lower wages than those prescribed by a trades union. [Cant] Note: "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." --Lord Mahon. Bamboo rat (Zo["o]l.), any Indian rodent of the genus Rhizomys. Beaver rat, Coast rat. (Zo["o]l.) See under Beaver and Coast. Blind rat (Zo["o]l.), the mole rat. Cotton rat (Zo["o]l.), a long-haired rat (Sigmodon hispidus), native of the Southern United States and Mexico. It makes its nest of cotton and is often injurious to the crop. Ground rat. See Ground Pig, under Ground. Hedgehog rat. See under Hedgehog. Kangaroo rat (Zo["o]l.), the potoroo. Norway rat (Zo["o]l.), the common brown rat. See Rat. Pouched rat. (Zo["o]l.) (a) See Pocket Gopher, under Pocket. (b) Any African rodent of the genus Cricetomys. Rat Indians (Ethnol.), a tribe of Indians dwelling near Fort Ukon, Alaska. They belong to Athabascan stock. Rat mole. (Zo["o]l.) See Mole rat, under Mole. Rat pit, an inclosed space into which rats are put to be killed by a dog for sport. Rat snake (Zo["o]l.), a large colubrine snake (Ptyas mucosus) very common in India and Ceylon. It enters dwellings, and destroys rats, chickens, etc. Spiny rat (Zo["o]l.), any South America rodent of the genus Echinomys. To smell a rat. See under Smell. Wood rat (Zo["o]l.), any American rat of the genus Neotoma, especially N. Floridana, common in the Southern United States. Its feet and belly are white.
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Audio Help [rat] Pronunciation Key noun, interjection, verb, rat·ted, rat·ting. 
