1. Common to both sexes.
2. A term applied, in grammar, to such nouns as have but one form of gender, either the masculine or feminine, to indicate animals of both sexes.
3. Sometimes applied to eunuchs and hermaphrodites.
4. (Figurative) Sexless; neither one thing nor the other.

Having one form or characteristics of either sex
Having the characteristics of, or adapted for use by, both sexes; sexless; effeminate; Grammar, with one form signifying both male and female