'tortie-patterned' originates from English, specifically the clipped word 'tortie' (from 'tortoiseshell') combined with the adjective-forming element '-patterned', where 'tortie' referred to 'tortoiseshell-colored' and '-patterned' indicates 'having a pattern'.

'tortie-patterned' was formed in modern English by clipping 'tortoiseshell' to the colloquial 'tortie' (recorded in the 20th century) and adding '-patterned' to describe coat markings.

Initially it meant 'having tortoiseshell coloring or markings'; over time the basic meaning has remained essentially the same, used descriptively for animal coats.