Definition of metachromasia in US English:


(also metachromasy)


  • 1The property of certain biological materials of staining a different color from that of the stain used.

    • ‘The metachromasy was found to be independent of phase transition temperature of vesicles.’
    • ‘In these cases, metachromasy is an indication of dimerization and polymerization of the adsorbed dyes.’
    • ‘The change in color of a dye which results from metachromasy is not due to a change in pH of an aqueous solution containing it.’
    • ‘In some conditions the increase of stirring time leads to a loss of metachromasy that is related to the dye deaggregation.’
    • ‘The literature contains numerous reviews of metachromasy, especially in the histological and histochemical journals.’
    1. 1.1 The property of certain stains of changing color in the presence of certain biological materials.
      • ‘Under these conditions PBs appeared light blue, while metachromasia was observed for globoid inclusions that stained purple-blue.’


Early 20th century: modern Latin, from meta- (expressing change) + Greek khrōma ‘color’.