having male and female flowers borne on separate individuals of the same species (contrast with monoecious).
Merriam-Webster Online Dictionary
dioecious (adjective)1.
having male reproductive organs in one individual and female in another
2.
having staminate and pistillate flowers borne on different individuals
dioecious (Wikipedia)
Dioecy (Greek: διοικία "two households"; adjective form: dioecious) is a characteristic of a species, meaning that it has distinct male and female individual organisms.Dioecious reproduction is biparental reproduction. Dioecy is one method that excludes self-fertilization and promotes allogamy (outcrossing), and thus tends to reduce the expression of recessive deleterious mutations present in a population.Flowering plants have several other methods of excluding self-fertilization, called self-incompatibility.