Definition of "dioecious"

Most plants are hermaphrodite, even if some of them (hazel, for example) keep their male and female flowers apart. But some plants are dioecious, i.e. they have separate sexes. Some of our most familiar wild plants, such as nettle and red campion, are dioecious. If your holly never has any berries, that's probably because it's a male.

2014 December 12, Ken Thompson, “Do plants have a gender? Most plants are hermaphrodite, but not all – and an interesting situation arises when only one sex is imported into the UK [print version: Alien plant species in search of a mate: Although most plants are hermaphrodite, some come in two distinct genders. So how does a single-sex community develop?, p. W28]”, in The Daily Telegraph (Weekend)‎