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Webster 1913 Edition

Noun.

One who, or that which, booms.

(Zool.)

A North American rodent, so named because it is said to make a booming noise. See

(Zool.)

A large male kangaroo.

One who works up a “boom”.

[Slang, U. S.]

boomer ‎(plural boomers)

An adult male kangaroo.
A baby boomer.
(US, mainly 1920-1930) A transient worker who would move from boom town to boom town in search of temporary work.
(US, nautical, military, slang) A nuclear ballistic missile submarine, SSBN.
- 1990, The Hunt For Red October:
  Distant contact, probably submerged. It's a wild guess, but I'd say we hit a boomer coming out of the barn. Could be a missile boat out of Polijarny.
(Britain) The bittern.
(Appalachia) A red squirrel.