v1.0
Published 01/10/24
bàrr m. [b̥ɑːɍ], previously often spelt bàr (DASG˄, s.v. bàr; for dialectal reflexes of this word, see SGDS Item 78). Mackay (≈1897, 94) gives ‘bar “the regularly waving bank of peats by the side” is Ice. bar “undulations on the surface of anything”’. Unable to corroborate either Mackay’s etymon or his Scottish Gaelic form, McDonald earlier (2009, 340) considers the loan uncertain, but later (2015, 155) likely. At a guess, Mackay is referring to an extended sense of SG bàrr (bàr). EG barr 
The vowel later lengthening in more northerly dialects of Scottish Gaelic, hence the usual current spelling bàrr.
essentially applies to the ‘top, tip or end’ of something (eDIL˄); in Scottish Gaelic, senses include ‘top, uppermost part of anything; point, as of a weapon or shoe; crop of grain, grass or vegetables; harvest; superiority; suet; cream, fat floating on the surface; scum; bread, food; acme; branch; height, hill; head, helmet; battlement; son; pee of an anchor’ (Dwelly 1911). The term barr-fhàd (with lenition of fàd m. ‘single peat’ in a closed compound, also barrad, with reduction) refers to the ‘uppermost layer of peat, immediately under the turf’. Mackay seems to be adapting this or a similar use of bàrr to align with Ice. bára f. ‘wave, billow’ and its metaphorical use ‘undulations or rough stripes on the surface of a thing’ (Cleasby 1874). ON bára would be expected to yield SG [̩b̥aːɾə].