v1.0
Publishing history:
v1.0: 01/10/24
bòl . Cox (2002a, 186) records SG Bòl Phluic [ ̩b̥ɔˑɫ̪ ˈfɫ̪uiʰkʲ] and Bòl Ruairidh [ ̩b̥ɔˑɫ̪ ˈɾuəɾʲi], Lewis place-names containing a family nickname and masculine personal name, respectively, in the genitive as specific, and derives bòl ‘animal couch’ from ON ból nt. in the sense ‘animal resting place, lair’ (NO); 
Also Cox 1991, 493; 1992, 138; 1994, 46, 57.
Although both Mackenzie and MacBain cite ON bol (sic).
But citing the sense ‘farmyard, yard’.
A. buaile and its forms
A 1. buaile [ˈb̥uələ], buala [ˈb̥uəɫ̪ə]
(i) buaile f. is found primarily in the senses ‘fold, for cattle (HSS 1828), sheep or cattle (Armstrong 1825), or stock in general (MacLennan 1925; Faclan bhon t-Sluagh˄; AFB˄ /buələ/); field, open or enclosed; field for cultivation; reclaimed land between crofts and moor (Faclan bhon t-Sluagh˄: Lewis); stall (ibid.: Coll and Gairloch), cow-stall (Robertson 1906b, 85); dairy (Armstrong); cattle herd (ibid.; Faclan bhon t-Sluagh˄: buaile, buai, Tiree, buaile mhart, Barra)’. The word is also used in the sense ‘circle’ in general, e.g. of animal pounds, meteorological phenomena, privileged groups in church, toys and in games (Faclan bhon t-Sluagh˄).
(ii) buala (Faclan bhon t-Sluagh˄, with a note ‘slipped under buaile’: [bu̜ɤɫə] ‘cow-stall’, Raasay) and bualla (MacLennan: ‘cow-stall’; Faclan bhon t-Sluagh˄, s.v. buabhall: ‘horse-stall’, Lewis) appear to be variant forms of buaile, with a non-palatal lateral.
A 2. buailidh [ˈb̥uəli], bualaidh [ˈb̥uəɫ̪i]
(i) buailidh is the normalised dative form of buaile (as a dental stem) and is found in the sense ‘dairy-house (Shaw 1780); dairy-stall, fold (Armstrong); cow-stall (Robertson); stall (Faclan bhon t-Sluagh˄: [bu̜ɤli], Sutherland, boolie [sic], Assynt; Wentworth 2003: f. (rarely) [b̥[uə]l’i], Gairloch)’.
(ii) bualaidh, with a non-palatal lateral, occurs also: ‘cow-stall (HSS; Robertson; MacLennan; Wentworth: f. [b̥[uə]Li], Gairloch; Faclan bhon t-Sluagh˄: [bu̜ɤɫi], Lochalsh), stall in a byre (ibid. [idem], Coigach)’.
A 3. A number of derivatives are found: buaileag with the diminutive suffix -ag (MacLennan; Faclan bhon t-Sluagh˄); buaileach ‘ox-stall’ with the suffix -ach (Shaw; HSS: f.), as well as buailteach with intrusive t: ‘ox-stall (Armstrong: m.); 
Although HSS takes buailteach to be a compound of buaile + teach ‘house’ (EG tech), cf. SG bàthach f. ‘byre’ < EG *bóthech (cf. eDIL˄, s.v. bó: botheach).
SG buaile f. (A 1–3; Ir. idem, Mx bwoailley (Broderick 2010, 8)) is from EG búaile ‘cow-house, byre; cattle-pen; (temporary) cattle-fold, booley at times of summer pasturage; yard, enclosure, paddock’ 
Kelly (2000, 43) translates ‘cattle enclosure’.
Cf. MacBain; and MacLennan.
B. bual and its forms
B 1. bual [ˈb̥uəɫ̪], buail [ˈb̥uəl´]
(i) bual, as in bual-cruidh ‘?herd’ (MacGregor 1874, 274). MacGregor was born near Ballater, but of Perthshire parents (Kidd 2016, 34).
(ii) buail (Kirk 1702 (in Campbell 1938, 80): ‘fold for great cattle’[, Aberfoyle]; Faclan bhon t-Sluagh˄: [bu:ɑlʹ] ‘stall’, [buɑlʹ] ‘stall for one cow’, Mull, [bu̟əl] ‘cow-stall’, Islay).
B 2. bobhal, boghal [ˈb̥o-əɫ̪]
(i) bobhal ‘?stall’ (MacFhearghuis 1983, 24: bobhal na bà, Lewis).
(ii) boghal ‘stall’ (Faclan bhon t-Sluagh˄: ‘the cow’s bed or stall in the byre’, Lewis).
B 3. badhail, baghail [ˈb̥a-əl´]
(i) badhail occurs in Nicolson 1881, probably in the sense ‘stall’, although MacIntosh earlier writes
(ii) baghail (Lochaber or East Perthshire).
Nicolson (≈1881, 8) reads, ‘Aithneachadh bó badhail, no fàilt a’ chruidh “The wandering cow’s welcome, or the kine’s salute”. Nicolson notes that his source (MacIntosh 1785, 2) explains this to mean that when a strange beast joins a herd the rest attack it. Nicolson continues, ‘[a]n ingenious commentator suggests as the proper reading Aithnichidh bò a badhail “A cow knows her own stall”, which makes good sense. But the noun badhail is Irish [in fact, the word does not seem to appear in either Lhuyd 1707 or O’Brien 1832 (1768), while O’Reilly 1864 (1817) gives only bàidheal ‘cow-stall’ after Shaw]; buabhail is our word for “stall”.’ MacIntosh collected his material in Lochaber and in his own East Perthshire and his own text reads Ai’nichidh ba baghail, no, fàilt a chruidh ‘the cattle’s salute, or, the strange cow’s welcome’, to which is added the footnote that ‘[w]hen a strange beast comes to the herd, every one attacks him’. (MacIntosh’s second edition (1819, 5) reads, Aithnichidh bò baghail, no, failt a chruidh ‘the strange cow’s welcome, or the kine’s salute’, with a footnote that ‘[o]n a cow’s first joining a herd, she is treated rather roughly; hence, in derision, her reception is termed a salute, or welcome’.) If baghail means ‘wandering’, the sentence does not make syntactical sense; hence Nicolson’s alteration from the indicative aithnichidh to the imperative aithnicheadh, so Dwelly (1911, s.v. badhal). However, MacPherson (≈1945, 356) gives the North Uist version of the proverb as Aithnichidh gach bò a buaball fèin ‘Each cow will know its own stall, i.e. everyone knows their own place’. MacIntosh’s original version, therefore, should probably be read as Aithnichidh bò a baghail, no fàilte a’ chruidh ‘A cow knows its stall, or [if not, it’ll get] the kine’s welcome, i.e. if you don’t know your place, others are sure to remind you’.
B 4. bàidheal [ˈb̥aːjəɫ̪]
(i) bàidheal (Robertson: ‘stall’, Arran), with a long monophthong, and
(ii) baidheal (Shaw), which may indicate the same, as Shaw does not show lengthmarks.
B 5. buaidheal, buaigheal [ˈb̥uəjəɫ̪]
(i) buaidheal (MacLeod 1840, 10: ‘cow-stall (Kidd 2016, 398)’; Robertson: ‘stall’).
(ii) buaigheal (McAlpine: f. [bŭăė’´-ghyall] ‘cow-stall’, Islay; HSS: m. ‘idem’; MacLennan: f. ‘idem’; Dieckhoff: s.v. buabhal; Faclan bhon t-Sluagh˄: ‘stall’, Arran; AFB˄: f. /buəjəL/ ‘idem’, Barra and Arran) and buaigheall (HSS: m. ‘cow-stall’; Faclan bhon t-Sluagh˄: ‘cattle stall(s)’, Barra).
B 6. buathall [ˈb̥uəhəɫ̪]
Medial th in the form buathall m. ‘cow-stall’ (Dwelly App.) may represent [h], as does Dieckhoff’s (1932: m., Glengarry) bh in buabhal [buɐhal] ‘cow-stall’), possibly hiatus.
Watson (1999, 350–51) discusses this variation.
B 7. buabhall [ˈb̥uəvəɫ̪]
Buabhall (HSS: m. ‘idem’; Robertson: ‘stall’; MacLennan: f. ‘cow-stall’; Faclan bhon t-Sluagh˄: ‘cow’s bed, stall’, Skye, [bu̜ɑu̜ɫ] ‘cow-stall’, Strontian); cf. bó a’ bhuabhaill-thulchainn ‘the cow of the end stall’ 
(Lochaber) Am mart a bhios sa bhuabhall-thulchainn, is toigh leatha e ‘the cow in the end stall likes it’.
[... is likely to be attended to first.]
B 8. buaball [ˈb̥uəb̥əɫ̪]
Buaball (Faclan bhon t-Sluagh˄: [bu̜əbəɫ] ‘cow-stall’, North Uist) and buabull (ibid.: South Uist ‘idem’). These forms have a medial stop. The difference between second-syllable <a> on the one hand and <u> on the other is insignificant, although unstressed [ə] is generally represented nowadays by <a> in modern Scottish Gaelic orthography.
B 9. buadhall, buaghal [ˈb̥uə-əɫ̪]
(i) buadhall (Robertson: ‘properly a stall for cattle, ... but used also for a horse-stall in Ardnamurchan, Mull, and Perth’).
(ii) buaghal (Faclan bhon t-Sluagh˄: ‘stall’, Skye; AFB˄: m. /buə.əL/ [although the pronunciation provided gives [ˈb̥uəvɑɫ̪]] ‘idem’, Lewis, Uist, Skye and Raasay).
Rather than bŏvĕllĭum ‘stall for oxen’ here, the related bŏvĕllum nt. ‘idem’ (for bŏvĭllum, a nominal use of bŏvĭllum nt. adj. ‘of oxen’) would yield EG */boβəl/ regularly. The medial fricative of */boβəl/ develops into [j] in bàidheal [ˈb̥aːjəɫ̪] (B 4) and buaidheal, buaigheal [ˈb̥uəjəɫ̪] (B 5); [h] in buathall [ˈb̥uəhəɫ̪] (B 6); [v] in buabhall [ˈb̥uəvəɫ̪] (B 7), which undergoes fortition in buaball [ˈb̥uəb̥əɫ̪] (B 8); 
Cf. the isolated example of /v/ > /b/ in SG sgrìobhadh [skr´iːb̥u] ‘writing’ in East Sutherland (SGDS Item 764, Point 144).
On the question of /ɑ/ before -l in unstressed syllables, see Ó Maolalaigh 2008, 163–67, 224–25.
C. buaill [?], bòl [ˈb̥ɔˑɫ̪]
(i) buaill ‘place for resting and milking’ (Mackenzie 1910, 384: Lewis; so MacBain 1911).
(ii) bòl (Cox ibid.: ‘animal couch’, recorded as generic in Lewis place-names, see above).
Mackenzie’s buaill may be an oblique case form of bual(l) [b̥uəɫ̪], for [ˈb̥o-əɫ̪] or [ˈb̥u-əɫ̪] (cf. bobhal, boghal (B 2)), with alternation between a disyllable (with a short vowel followed by hiatus) and a diphthong, as is occasionally found in Lewis (Cox 2022, 127–28). Although ON ból ‘animal resting place; lair’ would be expected to yield SG bòl regularly, under (ii) the spelling bòl represents [b̥ɔˑɫ̪], which, given the evidence above, seems likely to be a weakly stressed and therefore reduced form of bobhal (B 2). The senses ‘place for resting and milking’ and ‘animal couch’ may simply be extensions of ‘stall’.
Shaw cites bol for ‘cow’, but this a typesetting error for bo, i.e. bò.
The etymology of OScots bowall, bowell etc. ‘recess in a wall’ (cf. Scots bole) is obscure, although DOST˄ tentatively suggests it may be a variant of Eng. bevel, and it might be worth considering whether it was borrowed from Scottish Gaelic or directly from Latin.