From Latin fornix (“arch, vault; brothel”) Arch as in a passageway, it was customary for courtesans of the era to wait for their customers out of the rain under these archways.
This etymology is incomplete. You can help Wiktionary by elaborating on the origins of this term.
fornicate (comparative more fornicate, superlative most fornicate)
- Shaped like an arch or vault; resembling a fornix.
fornicate (third-person singular simple present fornicates, present participle fornicating, simple past and past participle fornicated)
- (intransitive) To commit fornication.
- second-person plural present indicative of fornicare
- second-person plural imperative of fornicare
- feminine plural of fornicato
- vocative masculine singular of fornicātus