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.

    • ‘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.’
    • ‘The literature contains numerous reviews of metachromasy, especially in the histological and histochemical journals.’
    • ‘The metachromasy was found to be independent of phase transition temperature of vesicles.’
    • ‘In some conditions the increase of stirring time leads to a loss of metachromasy that is related to the dye deaggregation.’
    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’.