A
From AVENwiki
A is the first letter of the English alphabet and can be used as a prefix meaning "not". Thus, "asexual" means "not sexual" and is derived in the same way as heterosexual, homosexual, and bisexual. Similarly to these other orientations, the prefix preceding "sexual" can sometimes be used as a slang term for someone of that sexual orientation. Also, "aromantic" is derived in a similar way.
