1) A black African, or a dark-skinned person.
It was fashionable to have black servants from the sixteenth century: 1601 Isabella Aethiops vulgo a blackmore ancilla Dominae Sauile, Elland. The word gave rise to a popular nickname: 1611 Richard Hunte alias Blackamore, Ingleton
1657 Christopher Styles otherwise Blackamore, Thorne and this may occasionally have stabilised as a late surname: 1661 Richard Blackamoore, Tankersley. The surname was present in Boston in Lincolnshire in the 1881 census where it seems unlikely to be a variant of the Devon surname Blackmore.