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v1.0: 01/10/24
biceir m. [ˈb̥iʰkʲəɾʲ], gen. idem, ‘wooden dish (with handles); beaker’ etc. Forms of this word differ in terms of (1) the length of the stressed vowel: (long [iː]) bíceir, bìocair, (short [i]) biceir, bicear, bigeir, bicein, bigein, bigirein, biogaran; (2) the quality of the post-stress velar plosive: (preaspirated, non-palatal [ʰk]) bìocar, (preaspirated, palatal [ʰkʲ]) bíceir, biceir, bicear, bicein, (voiceless, non-palatal [ɡ̊]) biogaran, (voiceless, palatal [ɡ̊ʲ]) bigeir, bigein, bigirein; and (3) the form of ending: (-Vr) bíceir, bìocair, biceir, bicear, bigeir, (-Vn) bicein, bigein, (-VrVn) bigirein, biogaran.
Senses include ‘beaker or bowl’ (MacDomhnuill 1741: bíceir), ‘cup’ (Shaw 1780: biceir), ‘cup; bottle; small (round) wooden dish with handles’ (Armstrong 1825: bicear; HSS 1828: biceir), ‘wooden cylindrical dish with hoops, often with handles’ (HSS 1828: bigein), ‘small wooden dish’ (Mackay 1829, 116, 352: biogaran), ‘wooden dish’ (MacBain 1911: biceir), ‘small wooden dish; drinking cup; bottle; beaker; luggie’ 
‘Small wooden dish or vessel with one or two handles formed from the projection upwards of one or two of the staves’ (SND˄).
Henderson (1910, 205) derives Rob Donn’s form biogaran (Mackay 1829, 116, 352) from ON bikarr m. ‘cup, beaker, goblet’ (NO), cf. Ice. bikarr ‘beaker, large drinking cup’ (Cleasby 1874); McDonald (2009, 342) considers the derivation uncertain. HSS (1828) and MacBain (1911), on the other hand, derive biceir from Scots bicker ‘beaker’.
ON bikar acc. would formally yield SG *biogar [ˈb̥iɡ̊əɾ], possibly *bigear [ˈb̥iɡ̊ʲəɾ]. The word does not appear in Early Gaelic and the variation in form in Scottish Gaelic may be due to a number of factors: (a) a loan from Eng. beaker /biːkə(ɹ)/, 
Eng. beaker < MEng. biker (< ON bikarr), with modern Eng. beaker apparently assimilated to Eng. beak, while the original English form is retained in Scots bicker (OED˄).
While for Scots biker [bɪkər] ‘wooden cup, drinking vessel, round wooden vessel with an upright handle on one side’, Jakobsen (≈1928) notes ON bikarr, he adds that ‘the preservation of the word in Shetland is certainly due to the influence of Lowland Scots’.