For one, this term is not originally from Latin and Greek, but from English and French:
-“Pie-” (french) = magpie (a bird). The french word has been adopted in the English.
-“-bald” comes from English (lack of hair)
-pie-bald = varriagated and partly coloured like a magpie. This term is also used to describe white and black horses
Medical significance of piebaldism – partial albinism
It is a rare disorder of melanocyte development which is inherited in an autosomal dominant way.
Clinically one finds:
-a triangular shaped depigmented patch on the forehead
-a congenital white forelock
Indira Gandhi, a former Indian prime minister is a known case of piebaldism
Source of information: Harms M. Dermatologica Helvetica (The Swiss Journal of Dermatology and Venereology