ONlwSG

dùsal m. [ˈd̪̥u̟ːs̪ɑɫ̪], [ˈd̪̥uːs̪ɑɫ̪], gen. dùsail -[al], and dùiseal [ˈd̪̥u̟ːʃɑɫ̪], [ˈd̪̥uːʃɑɫ̪], gen. dùiseil -[al], ‘doze, slumber’ are derived by Henderson (1910, 208, 214) from ON dúsa ‘to rest, repose’ (NO), cf. Nn. dusa, Bm. duse ‘to doze, rest’, as does MacLennan (1925), while MacBain (1911) seems to suggest a derivation from either ON dúsa or Eng. doze.

≈MacBain 1911, s.v. dùiseal: ‘dùiseal, dùsal “slumber”, from N[orse] dúsa “doze”, Eng. doze’; s.v. dùsal: ‘dùsal “slumber”, from the Eng. doze’.

Besides ON dúsa, Stewart (2004, 409) cites ON dús nt. ‘calm, lull’, as does McDonald (2009, 351).

HSS (1828), followed by MacLeod and Dewar (1839), suggests dùsal is a contraction of SG dùsgadh ‘waking’ + amhuil (amhail) ‘similar’, but the development is unlikely.

Scottish Gaelic forms are as follows:

A. SG dòsal
(i) dosal: Shaw 1780, who excludes lengthmarks throughout: ‘slumber’; Armstrong 1825: †dosal ‘slumber, sleep’ – Armstrong notes that Irish has the same form, but the Irish word appears only in O’Reilly’s (1817 and 1864 

In Gaelic script: dósal, in Roman script: dosal ‘slumber’.

) dictionary and was most likely adopted from Shaw 1780;
(ii) dòsal: HSS 1828: with a cross-reference to dùsal; Dwelly 1911: idem.

B. SG dùsal
(i) dusal: Armstrong 1825: ‘sleep’, without a lengthmark, but citing Stewart and Stewart (1804, 331) and the marginal gloss for Matha XXV: 5 (An Tiomnadh Nuadh 1767), which both show a lengthmark; MacLeod and Dewar 1839: ‘slumber; also dust, dustiness’;
(ii) dùsal: HSS 1828: ‘slumber’, citing the marginal gloss for Salm CXXI: 4 (e.g. Am Bìoball 1807); M^cAlpine 1832: dusal [dûs´-al] ‘slumber’; Dwelly 1911, s.v. dùsal: ‘dùiseal [see under (C.), below]; quirk; dust, dustiness’: rinn iad dùsal “they slept” ’; MacLennan 1925, s.v. dùsal: [doosal] ‘slumber’ (also noted under dùiseal (C.)); AFB^˄: /duːsəL/ ‘doze, nap, slumber’, Lewis, Skye, Mull.

C. SG dùiseal
(i) duiseal: Armstrong 1825: ‘cloud, gloom, heaviness, dulness, drowsiness’;
(ii) dùiseal: HSS 1828, citing Gillies (1786, 77), with a cross-reference to dùsal; MacLeod and Dewar 1839: idem; MacEachen 1842: ‘slumber, drowsiness’; Dwelly 1911: ‘cloud; gloom, heaviness; dulness; spell of work; slumber, drowsiness’; MacLennan 1925, s.v. dùiseal: ‘dùiseal, dùsal [dooshal] “slumber, drowsiness” ’; Dieckhoff 1932: duiseal [duːSal] ‘slumber’, Glengarry; Wentworth 2003, s.v. doze: dùsál [d̥uːsɑʟ], Gairloch; Faclan bhon t-Sluagh^˄: ‘dozing, not fully asleep’, South Uist; AFB^˄: /duːʃəL/ ‘cloud, gloom; doze, nap, slumber’, South Uist and Argyllshire.

While phonetically ON dúsa could formally provide a base for SG dùsal, the probable development dòsal > dùsal > dùiseal and the more southerly provenance of the word seems to favour a loan from Scots doze (Eng. doze) + the Gaelic verbal noun ending -ail/-al; cf. also the denominative verb Scots dozen [ˈdoːzən] ‘to be or become cold, numb’, past part. dozened (also contracted to dozen) ‘stupified, dazed, impotent; dull, stupid, heavy with sleep’ (SND^˄).

The senses ‘dust, dustiness’ given by MacLeod and Dewar (1839) and Dwelly (1911) for dùsal under B(i) and (ii), above, suggest conflation with dusal ‘dust etc.’, s.v. dus.