word-forming element meaning "all," from Latin omni-, combining form of omnis "all, every, the whole, of every kind," a word of unknown origin, perhaps literally "abundant," from *op-ni-, from PIE root *op- "to work, produce in abundance."
1650s, "of or pertaining to the fact of being male or female," from Late Latin sexualis "relating to sex," from Latin sexus (see sex (n.)). Meaning "pertaining to copulation or generation" is from 1766; sexual intercourse attested by 1771; sexual orientation by 1967; sexual harassment by 1975. Sexual revolution attested by 1962. Sexual politics is from 1970. Related: Sexually.