Pronunciation AHD: boo͞m IPA: /buːm/ SAMPA: /bu:m/ noun A period of prosperity or market activity Long spar to extend foot of a sail A horizontal member of a crane or derrick, used for lifting. An abrupt, low-pitched sound, such as of an explosion. (The boom of the surf) Translations català: botavara f (2) Chinese: 繁荣, 隆隆声, 激增 Dutch: hoogconjunctuur, hausse (1) French: hausse (1) German: Aufschwung m (1), Baum m (2), Ausleger m (3), Brausen n (4) interjection The sound of an explosion. Translations Dutch: boem French: boum German: Bumm intransitive verb To be prosperous. (Business was booming.) To speak or make noise with an intense, low pitch. Translations German: blühen (1), dröhnen (2) Dutch noun A tree