(1) A property of a dye in which the resulting color of the stain is different from the color of the dye solution
(2) A characteristic of a biological cell or tissue in which the color rendered following staining is different from the color of the dye
For instance, volutin granules in bacteria (e.g. Corynebacterium spp. and Mycobacterium spp.) stain pink with methylene blue.
Word origin: Greek meta (after) + Greek chrôma (color)