Adjective
(botany) Having male (staminate), female (pistillate), and bisexual flowers on the same plant (also known as "polygamous"), like Fraxinus excelsior
(botany) Belonging to the former Linnæan order Trioecia, consisting of plants of this type.
(zoology) Having three sexes: male, female and hermaphrodite, as some nematodes.
Source: en.wiktionary.org