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gorillagram

British  
/ ɡəˈrɪləˌɡræm /

noun

  1. informal  a jocular greetings message delivered to someone celebrating a birthday, engagement, etc, by a person dressed as a gorilla

"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 gorillagram

C20: from gorilla + ( tele ) gram