(US, historical) A member of a 19th century movement which campaigned for the opening of "Unassigned Lands" within the Indian Territory (now Oklahoma) for settlement.

(chiefly informal) Alternative letter-case form of boomer (“baby boomer”)

An adult male kangaroo.

Something that makes a booming sound.

(US, mainly 1920–1930) A transient worker who would move from boom town to boom town in search of temporary work.

A device used to bind or tighten chain.

(US, nautical, military, slang) A nuclear ballistic missile submarine, SSBN.

(UK) A bittern (subfamily Botaurinae).

(Appalachia) A red squirrel (Tamiasciurus hudsonicus).

A mountain beaver (Aplodontia rufa).

(US, historical) Alternative letter-case form of Boomer (“Oklahoma settler”)

(informal) Ellipsis of baby boomer.

(by extension, slang, sometimes derogatory) An elderly person, regardless of generation.

(by extension, slang, sometimes derogatory) A person who is too old to be familiar with the use of recent technology.