What does fellatio mean?
Fellatio is a formal, clinical term for oral stimulation of the penis — one of the principal forms of oral sex. Borrowed directly from Latin, it functions in English as a mass noun and belongs chiefly to medical, scientific, legal, and educational writing; in everyday speech people more often say 'oral sex' informally or use slang such as 'blow job.' The related verbs and agent nouns — 'fellate,' 'fellator,' 'fellatrix' — share its Latin root. Because the word carries no inherent slang coloring, it appears comfortably in textbooks, public-health guidance, court records, and dictionaries where cruder vocabulary would be inappropriate, yet it remains explicit in meaning and can still startle in casual contexts. Its counterpart for oral stimulation of the vulva is 'cunnilingus,' a parallel Latin borrowing. For writers, the value of 'fellatio' lies in its precision and neutrality: it names a specific act unambiguously, without either clinical coldness beyond register or the coarser tone of slang, making it the default choice wherever accuracy and decorum must coexist.
nounOral stimulation of the penis; a form of oral sex performed on a man or male.
- Oral stimulation of the penis, typically as a sexual act.
"The health pamphlet explained that fellatio still carries some risk of sexually transmitted infections."
"The study surveyed adults' attitudes toward fellatio within long-term relationships."
"In the novel's frank discussion of intimacy, the narrator mentions fellatio without euphemism."
A regular English plural exists but is seldom used, since the noun normally functions as a mass noun referring to the act rather than to countable instances.
"The survey recorded how frequently participants reported giving or receiving fellatios."
Though it names an ancient act, 'fellatio' didn't appear widely in English print until the 19th century — Latin gave Victorians a polite-sounding way to write about the unspeakable.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of fellatio
Fellatio comes from Latin, derived from the verb 'fellare,' meaning 'to suck,' which in turn traces to the Proto-Indo-European root *dhelh- (*dhl̥h-), associated with sucking and swelling. The Latin noun 'fellatio' denoted the act itself, and English adopted it directly as a learned borrowing, becoming common in printed English during the 19th century as medical and sexological writing expanded. Cognates within English are essentially its own derivatives — fellate (a later back-formation), fellation (borrowed via French), and the agent nouns fellator and fellatrix.
Related word forms
How fellatio is actually used
'Fellatio' is a clinical or formal register term; everyday conversation favors 'blow job' (informal) or the neutral phrase 'oral sex.' The standard English plural 'fellatios' exists but is rarely needed since the noun is usually uncountable in practice. Although Latin in form, the word takes ordinary English verb agreement ('fellatio is'), not Latin neuter plural treatment.
Easily confused with fellatio
Cunnilingus is oral stimulation of the vulva (female anatomy), whereas fellatio is oral stimulation of the penis.