What does dioecious mean?
Dioecious describes a plant or animal species whose individuals are divided into distinct males and females, with each individual bearing only one kind of reproductive organ. The word is most familiar from botany: dioecious plants such as holly, willow, kiwi, and ginkgo require both sexes to be present for pollination and fruit production, since no single tree can fertilise itself or its neighbours alone. Its opposite is monoecious, describing species in which male and female structures occur on the same individual. Derived from Greek roots meaning 'two houses', dioecious belongs mainly to scientific register and appears most often in biology, horticulture, and gardening contexts, where knowing a species' breeding system has practical consequences for growers.
adjectiveOf a plant or animal species, having male and female reproductive organs on separate individuals, so that each individual is distinctly male or female.
- (of plants and animals) having male and female reproductive structures on separate individuals of the same species.
"Holly is dioecious, so a female tree must grow near a male one to produce berries."
"Willows are dioecious, with male catkins on some trees and female catkins on others."
"In many dioecious animals, such as humans, sex is determined at fertilisation."
The word literally means 'two houses' — and holly bushes take it seriously: every bush is strictly male or strictly female, which is why some hollies never produce a single berry.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of dioecious
Dioecious derives from Greek 'di-', meaning 'two', plus 'oikos', meaning 'house', so it literally signifies 'two houses' — male and female organs housed on different individuals. It entered English in the early eighteenth century by way of New Latin 'dioecius', coined for biological classification. The Greek root 'oikos' also underlies words such as 'ecology' and 'economy', making them distant cognates.
Related word forms
How dioecious is actually used
A technical term used chiefly in botany and zoology; rare outside scientific writing but well established there. The spelling variant 'diecious' also exists but 'dioecious' is the standard form.
Easily confused with dioecious
Monoecious organisms bear both male and female reproductive organs on the same individual, whereas dioecious ones have them on separate individuals.