Well the modern usage of “bisexual” regarding sexual orientation has also found its way into science, evidenced by the lack of prominent scientific synonyms
Which again is irritating because scientific terminology shouldn’t be this lax
I think “bisexual” only references two sexes because it was created to describe a phenomenon related to sexual reproduction which evolved to occur between two main sexes; the term was unrelated to gender
It could also be applied to animals meaning something that nowadays would be described as “intersex”.
I just think this meaning makes much more sense than “being attracted to two (later multiple) sexes”. If about sexuality and not sex, “bisexual” should just mean “with sexuality related to the number two” based on the etymology.
Actually it originally refers to having two sexes. Aka hermaphroditic.
I really hate how the word “sexual” has evolved in meaning into “relating to the activity that evolved to happen between the two main sexes”. We have the perfectly good Greek root “ero” and for some reason we have gradually muddled up the meaning of “sexual”.
…thats even worse 💀