n An adult male kangaroo.
n Something that makes a booming sound.
n (US, mainly 1920–1930) A transient worker who would move from boom town to boom town in search of temporary work.
n A device used to bind or tighten chain.
n (US, nautical, military, slang) A nuclear ballistic missile submarine, SSBN.
n (UK) A bittern (subfamily Botaurinae).
n (Appalachia) A red squirrel (Tamiasciurus hudsonicus).
n A mountain beaver (Aplodontia rufa).
n (realtime strategy games) A player who prioritises economic development and securing resources (and therefore future production) over offence or defence.
n (by extension, slang, sometimes derogatory) An elderly person, regardless of generation.
n (by extension, slang, sometimes derogatory) A person who is too old to be familiar with the use of recent technology.
n A surname.
n (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.
n (US, historical) Alternative letter-case form of Boomer (“Oklahoma settler”) [A surname.]
n (informal) Ellipsis of baby boomer. [(sometimes capitalized) A person born in the postwar years (generally considered in the United States and other Allied countries as between 1946 and the early 1960s), when there was a marked increase in birthrates throughout the Western world following the return of servicemen at the end of World War II.]