Mid 19th century; earliest use found in British Florist. From scientific Latin allochrous or its etymon ancient Greek ἀλλόχροος (contracted ἀλλόχρους) changed in colour + -ous.
Definition of allochroous in US English:
allochroous
(also allochrous)
adjectiveˌaləˈkrəʊəs
rare
Changeable in colour, iridescent.
Origin
Mid 19th century; earliest use found in British Florist. From scientific Latin allochrous or its etymon ancient Greek ἀλλόχροος (contracted ἀλλόχρους) changed in colour + -ous.