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exacum

British  
/ ˈɛksəkəm /

noun

  1. any plant of the annual or perennial tropical genus Exacum; some are grown as greenhouse biennials for their bluish-purple platter-shaped flowers: family Gentianaceae

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of exacum

Latin, a name for centaury, from ex out + agere to drive