Etymology
Advertisement
arms race (n.)
1930, in reference to naval build-ups, from arms (see arm (n.2)) + race (n.1). First used in British English.
Related entries & more 
Advertisement
rat-hole (n.)

also rathole, "the hole gnawed in woodwork, etc., by a rat or rats," 1812 first in the figurative sense of "nasty, messy place;" from rat (n.) + hole (n.). As "bottomless hole" (especially one where money goes) by 1921.

Related entries & more 
rat-pack (n.)

1951, "a gang of disorderly young people" [OED], from rat (n.) + pack (n.). In reference to the Hollywood circle around Frank Sinatra, from 1958.

Related entries & more 
rat-trap (n.)

"trap for catching rats," late 15c., rat trappe, from rat (n.) + trap (n.).

Related entries & more 
rat-poison (n.)

"something used to poison rats with," especially arsenic, 1799, from rat (n.) + poison (n.).

Related entries & more 
Advertisement
pack-rat (n.)
common name for the North American bushytailed woodrat (Neotoma cinerea) 1885, from pack (v.); so called from the rodents' habit of dragging objects off to their holes. Used figuratively or allusively from c. 1850 of persons who won't discard anything, which means either the rat's name is older than the record or the human sense is the original one.
Related entries & more 
rugrat (n.)

also rug-rat, "baby, small child," by 1968; see rug + rat (n.).

Related entries & more 
ratty (adj.)

1856, "resembling a rat;" 1865, "full of rats;" 1867, "wretched, miserable, shabby," from rat (n.) + -y (2). An older word for "resembling a rat" is rattish (1680s).

Related entries & more 
ratbag (n.)
also rat-bag, "unpleasant person," 1937, from rat (n.) + bag (n.).
Related entries & more 
ratsbane (n.)

"rat poison, arsenic," 1520s; see rat (n.) + bane. Compare henbane, fleabane, wolfsbane.

Related entries & more 

Page 3