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I was reading this Reddit post's comments: 'I am the guy with two penises. AMA' (NSFW), and came upon this discussion (of sorts), where the plural of "penis" has been suggested to be either: "penises", "penii", or "penes".

I looked it up and Wiktionary states that "The hyperforeign Latinate penii is occasionally used as the plural in modern English."

Is "penii" or "penes" also correct in other contexts (medical or scientific, perhaps)? What are the correct plural forms of "penis"?

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marked as duplicate by tchrist, medica, Mari-Lou A, Canis Lupus, Janus Bahs Jacquet Jan 2 '14 at 10:58

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

In precisely what language and declension does -is in the singular ever become -ii in the plural? You only get -ii plurals in Latin starting from -ius singulars, a situation which clearly does not here obtain. – tchrist Jan 2 '14 at 4:45
The plural of penis is penes (in some medical literature) or penises. – medica Jan 2 '14 at 4:52

Th plural of penis is penises or penes. All the dictionaries are consistent so I don't know what this discussion is all about.


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Word Origin & History penis 1676, perhaps from Fr. pénis or directly from L. penis "penis," earlier "tail" (cf. Eng. tail in both senses, the sexual one slang), from PIE *pes-/*pesos- "penis" (cf. Skt. pasas-, Gk. peos, posthe "penis," probably also O.E. fæsl "progeny, offspring," O.N. fösull, Ger. Fasel "young of animals, brood"). The proper plural is penes. The adj. is penial. In psychological writing, penis envy is attested from 1924. – Peter Jan 2 '14 at 8:58
Wiktionary states, regarding "penii": "The hyperforeign Latinate penii is occasionally used as the plural in modern English." – galacticninja Jan 2 '14 at 10:05

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