1. a drawing, diagram, or other symbol that represents a specific quantity of or other fact about the thing depicted: Every isotype of a house on that chart represents a thousand new houses.
  2. a statistical graph, chart, diagram, etc., that employs such symbols.
  3. Biology. any of two or more separate populations of the same or a similar type.
  4. Immunology. any antigenic determinant that is common to all individuals in a species.

Origin of isotype

First recorded in 1880–85; iso- + type Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

isotype in Medicine


  1. An antigenic marker that occurs in all members of a subclass of an immunoglobulin class.
Related formsi′so•typic (-tĭpĭk) adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.