v1.2
Publishing history:
v1.0: 01/10/24
v1.1: 15/07/25
v1.2: 22/07/25
làmhaidh m. [ˈɫ̪ɑ̃ːvi] 
Cf. /Laːvɪ/ (AFB˄).
A. làmhaidh, làmhach, làmhadh
A 1. làmhaidh [ˈɫ̪ɑ̃ːvi]
(i) làmhaidh (Dwelly 1911; MacLennan 1925; MacDonald 1946, 39: Lewis 
Cf. the proverbial phrase cho tiugh ’s a tha làmhaidh anns an Eilean Mhòr (≈ibid.) ‘as plentiful as guillemot in An t-Eilean Mòr’. An t-Eilean Mòr is the largest of the Flannan Isles NA724468.
Fergusson, Forbes and Mackay eschew lengthmarks; so also MacKenzie who translates lamhaidh as ‘a handful’, on the assumption that the word is based on SG làmh ‘hand’; Henderson’s lamhaidh silently ‘corrects’ Mackay’s spelling lamhidh; Lockwood more recently gives làmhaidh (see (i)).
(ii) laimhidh (Ross 1890, 
Who neglects lengthmarks.
(iii) lavi (Christiansen 1938, 4, 16) for làmhaidh, in an unconventional orthography; also lavie (Macaulay 1764, 149) and lavy (Martin 1698, 94, 106: St Kilda; Buchan 1727, 8, 20; Ross 1890), if these are not scotticisations;
(iv) waavi (MacFhearghuis 1995, 144): while her husband Peter MacLachlan was serving as minister on St Kilda between 1906–1909, Alice MacLachlan (née Sgroggie), who was originally from Haddington, East Lothian, kept a diary (Riches 2021˄) in which she gives the English phonetic spelling waavi, with <w> representing a St Kilda reflex of SG l (cf. SGDS Item 554 Point 15: làmhan [wɑːvən] pl. ‘hands’);
(v) lamh, ?for làmh: Henderson (1910, 126) writes ‘in Lewis [the guillemot] exists as lamh’, but lamh is attested nowhere else and seems to be a ghost word; ?cf. làmhach (A 2).
A 2. làmhach [ˈɫ̪ɑ̃ːvəx], -[ax], -[ɔx]
(Faclan bhon t-Sluagh˄: Lewis).
A 3. làmhadh [ˈɫ̪ɑ̃ːvəɣ]
(Faclan bhon t-Sluagh˄: Skye).
B. langaidh, langach
B 1. langaidh [ˈɫ̪ɑ̃ŋɡi]
(i) langaidh (Fergusson 1886, 81: Barra; CG VI, 94; Forbes 1905, 32, 280; Dwelly 1911; Lockwood 1961, 51–52; 1984, 93; McDonald 1972: Uist; Garvie 1999, 62; AFB˄); misspelt langidh (Forbes 1905, 280); anglicised as langy (Lockwood 1984, 93);
(ii) langaid (MacBain 1896; 1911; Forbes 1905, 32; Dwelly 1911; MacLennan 1925: f.; Lockwood 1961, 51–52; An Stòr-Dàta 1993; AFB˄): this word, despite being cited by a succession of authorities, seems to be a ghost word: it first appears in MacBain’s Etymological Dictionary of the Gaelic Language (≈1896; 1911): ‘langaid, the guillemot (Hebrides); from Scots (Shetland) longie, Dan. langivie ...’, in which we should probably read langaidh rather than langaid: the immediately preceding entry reads ‘langaid, a fetter, fetters ...’.
(iii) longaid: under guillemot, An Stòr-Dàta (≈1993) gives ‘eun dubh an sgadain, eun a’ chrùbain, falcag bhiorach, gearra-breac, làmhaidh, langach, langaid, longaid’, but longaid is unattested elsewhere and may be a ghost word: the form obviously missing from this list is langaidh, and it may be that ‘langaid, longaid’ were inadvertently included rather than ‘langaidh, langaid’; for langaid, see (ii).
B 2. langach [ˈɫ̪ɑ̃ŋɡəx], -[ax], -[ɔx]
(Fergusson 1886, 81; ≈Mac Coinnich 1899, 314: Lewis 
In dh’itheadh tu trì dhe na Seumais-Ruadha, dh’itheadh tu dhà dhe na duibh-eunaich, ach dhèanadh an langach sàth do chridhe dhuit ‘you could eat three puffins, you could eat two razorbills, but a single guillemot would be enough to satisfy you’.
Henderson (1910, 126) derives SG làmhaidh from ON lang-vé m. ‘guillemot’, so also Christiansen (1938, 16: langve) and Sommerfelt (1952a, 230: langvia); Mackay (1897, 93) cites Ice. langve. Lockwood (1961, 51–52: langvé; 1984, 94: *langvī
The printed form *langvī-i is a typesetting error.
ON lang-vé
The compound ON lang-vé (Ice. lang-vía) consists of lang-, the stem form of langr adj. ‘long’, + *vé ‘a type of bird’, which de Vries (1962) compares with Dut. wouw ‘kite’, but for which Lockwood (1972, 47–48; 1984, 97) sees an onomatopoeic origin.
The oblique, palatalised form of SG -ach was -igh /iɣ´/ [iʝ], before developing into -ich /ix´/ [iç] (O’Rahilly 1976, 56–;57; Watson 1904, xxxiv–xxxv).
Interpreting SG -[i] as -idh /i/ [i], the oblique, palatalised form of -adh /əɣ/ [əɣ].