a. [ L. rosaceus, fr. rosa rose. ] 1. (Bot.) (a) Of or pertaining to a natural order of plants (Rosaceae) of which the rose is the type. It includes also the plums and cherries, meadowsweet, brambles, the strawberry, the hawthorn, applies, pears, service trees, and quinces. (b) Like a rose in shape or appearance; as, a rosaceous corolla. [ 1913 Webster ]

2. Of a pure purpish pink color. [ 1913 Webster ]