v1.0
Published 01/10/24
pit f. [pʰiʰtʲ], 
Cf. [peet] (MacLennan 1925, s.v. pit), /pihdʲ/ (AFB˄), (Benbecula) [p´iχ´t´] (LASID IV, 232, Item 482), (Lewis) [p´ihṭ´] (ibid., 252, Item 482), (Gairloch) [pʰiht’] (Wentworth 2003, s.vv. cunt, fanny, vulva).
gen. pite -[ə], ‘vulva’. Sommerfelt (1949, 235) derives Ir. pit (Donegal) [p´èt´] ‘pudenda’ 
Cf. Dinneen 1947, s.v. pit; de Bhaldraithe 1959, s.v. vulva; Ó Dónaill 1977, s.vv. pit, pis; (Galway) /p´iʃ/ generally, but /p´it´/ as swear word (Ó Curnáin 2007 I, 138, IV, 2562).
from an Old Norse word ‘corresponding to Scandinavian fette, fitte’, cf. Norw. fitte (Ordbøkene˄, s.v.), Dan. fitte, fisse (ODS˄, s.vv.).
SG pit in the sense ‘vulva’ is first attested in Alasdair Mac Mhaighstir Alasdair’s satirical poem ‘Marbhrainn Máiri nian Ean Mhic-Eun, do ’n gairte, an Aigionnach’ (Mac-Dhonuill 1751, 153–58: 155, 157); it is listed in Shaw 1780 (‘hollow, pit, female privities’) and in Armstrong 1825, where Greek characters are used in order, one assumes, to protect the sensibility of non-academic readers: ‘pit, hollow; θε μοστ κο μμον ναμε φορ θε σεκρετ παρτς οφ α φεμαλε [the most common name for the secret parts of a female]’. A folk etymology in the 9th-century Sanas Cormaic (Early Irish Glossaries Database˄, s.v. putte YAdd.1060) connects OG pit with Lat. pūtĕo ‘to stink’: Putte a putteo .i. cuthe, ut dicitur pit a puteo .i. brenaim ... [‘putte is from putteo, i.e. putte means “a pit”; as stated pit 
Glossed Lat. cunnus ‘vulva’ by Stokes (1868, 138).
is from pūtĕo “to stink” ’].
Lat. pūtĕo ‘to stink’ is cognate with ON fuð- ‘vulva’ (attested for example in the compound fuð-flogi ‘a man who runs away from his betrothed’ (NO)), Ice. fuð, Norw. fud, fu, Germ. Fotze and Scots fud ‘the buttocks; the female pubes or pudendum etc.’ (de Vries 1962).
Lat. pŭtĕus ‘a well’ yields OG cuithe (Cormac’s cuthe) ‘pit; well etc.’ (McManus 1983, 22, 28, 30, 41 fn 48, 48–49, 58, 64; 1984, 150: borrowed into Primitive Irish), apparently OEng. pyt(t) ‘pit’ (OED˄: via a Germanic base) and possibly W pyd ‘danger; pit, trap etc.’ (GPC˄: via *puti̯us). MacBain (1911) derives SG pit ‘hollow or pit; κύσθος [“female genitals”]’ – along with Ir. pit and Mx pitt 
Y Kelly 1866: ‘pudendum muliebre [“female genitals”], a pit’, but the sense ‘pit’ may have been imposed from English pit (cf. Kelly 1991˄, which has ‘vagina, vulva’ only).
– from Old English, while Vendryes (1996) takes OG pit to be from British or Welsh.
McDonald (2009, 352–53) considers the derivation uncertain.
ON *fitte would be expected to yield SG *fite *[ˈfiʰtʲə] in the first instance, which might yield *pite *[ˈpʰiʰtʲə] via back-formation and delenition of initial /f/ > /p/, which might in turn yield pit via apocope, or levelling based on nouns with rad. sing. -∅ ~ gen. sing. -e. However, given that pit/pitt in the sense ‘vulva’ is found not only in Scottish Gaelic but also in Irish and Manx, and given the likely antiquity of the word in this sense in Gaelic, the phonetically more straightforward development from OEng. pyt(t) seems on the whole more probable.
MacBain (1911) notes of SG pit that the senses ‘hollow, pit’ appear in dictionaries (e.g. Shaw 1780, Armstrong 1825, HSS 1828) ‘due to the supposed force of topographic pit [“farm holding etc.”]’, e.g. SG Peit/Baile na Craoibhe or Peit/Baile nan Craobh ‘the farm at the tree’ (Taylor 2011, s.v. Pittencrieff) NO372159 (for EG pet(t), see for example Cox 1997; 2008c): at any rate, SG peit (anglicised as Pit- in place-names) appears to have no connection with SG pit ‘vulva etc.’