[ trahy-soh-mee ]

  1. an abnormality characterized by the presence of an additional chromosome to the normal diploid number.

Origin of trisomy

First recorded in 1925–30; tri- + -some3 + -y3

Words Nearby trisomy Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use trisomy in a sentence

British Dictionary definitions for trisomy


/ (ˈtraɪsəʊmɪ) /

  1. the condition of having one chromosome of the set represented three times in an otherwise diploid organism, cell, etc. Trisomy of chromosome 21 results in Down's syndrome

Origin of trisomy

C20: from tri- + (chromo) som (e) + -y ³

Derived forms of trisomy

  • trisomic (traɪˈsəʊmɪk), adjective

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

Scientific definitions for trisomy


[ trī-sōmē, trīsō′- ]

  1. The condition of having three copies of a given chromosome in each body cell rather than the normal number of two.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.