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polysomic

British  
/ ˌpɒlɪˈsəʊmɪk /

adjective

  1. of, relating to, or designating a basically diploid chromosome complement, in which some but not all the chromosomes are represented more than twice

"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 polysomic

C20: from poly- + -some ³ + -ic