fellatio (n.)
1894 (Havelock Ellis), from Latin fellatio, noun of action from fellatus, past participle of fellare "to suck," from suffixed form of PIE root *dhe(i)- "to suck." The sexual partner performing fellatio is a fellator; if female, a fellatrice or fellatrix. L.C. Smithers' 1884 translation from German of Forberg's "Manual of Classical Erotology" has fellator, fellatrix, and fellation, but not fellatio.