'eggplant-colored' originates from modern English as a compound of 'eggplant' + 'colored' (US spelling) or 'eggplant' + 'coloured' (UK spelling). 'eggplant' is a common North American name for the vegetable also called 'aubergine' in British English.

'eggplant' entered English in the 18th century referring to varieties that resembled eggs in shape (hence 'egg' + 'plant'). The word 'aubergine' comes via French from Arabic and ultimately from Persian/Dravidian sources; 'color/colour' comes from Old French 'colourer' and Latin 'color'. The compound adjective developed by straightforward combination of the noun for the vegetable and the participial adjective 'colored/coloured'.

Initially the components referred literally to the vegetable ('eggplant') and the property of having color ('colored'); over time the compound came to be used specifically to describe a particular dark purplish hue associated with the eggplant, rather than anything to do with the plant itself.