Douglas Harper's Etymology Dictionary
Wiktionary
trisexual
Etymology 1 a. (context sexuality English) Of or relating to a system that involves three genders, or sexuality. Etymology 2
a. (context humorous or pejorative English) Of a person, willing to "try anything" sexually. n. One who is trisexual.
Usage examples of "trisexual".
The middle portion of my novel The Gods Themselves, with its intricate picture of a trisexual society, has been interpreted psychiatrically and philosophically in ways that I know I didn intend, and in terms that I literally don understand.