Publishing history:v1.0
v1.0: 15/06/25
geinn 
Written gèinn in AFB˄, a form which excludes pronunciations with a diphthong. Dwelly (1911) gives the form geinn, but this is unjustifiably altered to gèinn in AFB˄’s version of Dwelly.
f., sometimes m., [ɡ̊ẽĩɲ], 
Cf. (Gairloch) [ɡ̊[ɤi]N’], [ɡ̊[ëi]N’] (Wentworth 2003, s.v. wedge).
[ɡ̊ẽːɲ], 
Cf. (Glengarry) [gˈjéːNˈj] (Dieckhoff 1932).
gen. geinne [ˈɡ̊ẽɲə], ‘wedge’ is derived by Henderson (1910, 119) from ON gand, gann [sic] ‘peg, stick’ – ON gandr m. has the senses ‘stick used by trolls for sorcery; sorcery’ (NO) – but Oftedal (1962a, 119) notes that a derivation from Old Norse cannot be satisfactorily explained – an accusative gand would be expected to yield SG *gannd *[ɡ̊ãũᵰ̪d̪̥] in the first instance – and in consequence McDonald (2009, 356) considers the loan unlikely.
SG geinn is a native word that goes back to EG genn, geinn f. ‘wedge; block of wood etc.’ (eDIL˄); it is cognate with W gaing, Bret. genn and ultimately ON gandr (MacBain 1911; MacLennan 1925; GPC˄).