ONlwSG

branndair m. [ˈb̥ɾãũᵰ̪d̪̥aɾʲ], [ˈb̥ɾãũᵰ̪d̪̥ɛɾʲ], 

(Skye) [bɾ[ɑu̜]n̪d̪ɑɾ] (Faclan bhon t-Sluagh^˄); (Islay) [bɾɛ̃n̪d̪ɑɾ] (ibid.); (Gairloch) [b̥r[ɛ̃u]Nd̥ɑr̆’] (Wentworth 2003); (Glengarry) [brä(au)Nːderˈ] (Dieckhoff 1932); (Easter Ross) /brɑ̃ũdər/ (Watson 2022, 127); [braund΄-ăr‘] (MacLennan 1925); /brãũNdɛrʲ/ (AFB^˄).

gen. idem, ‘gridirion; grate; slatted shelf’; cf. EG brannraḋ m., Ir. brannradh m. ‘idem’. SG branndair and Ir. brannradh are tentatively derived from ON brandreið f. ‘gridirion’ or OEng. brandreda by Craigie (1894, 158 

Also [EG] brann ‘(fire)brand’ from ON brandr or OEng. brand, although eDIL^˄ derives it from Old English.

), 

McDonald (≈2009, 345) opines that ‘metathesis of ON -r-d- or Ir. -r-d- to SG -dr- is not problematic’: this seems to assume that Craigie’s (OEng.) brandreda is a variant of (ON) brandreið and that EG <ḋ> (frequently written d), Ir. <dh> and SG <d> are interchangeable, whereas (non-palatal) EG <ḋ> represents /ð/ (before falling together with /ɣ/ during the 12th century (Thurneysen 1975, 76–77), although it comes to be written dh with the spread of the use of <h> to mark lenition) while Ir. and SG <d> (written t or d(d) in Early Gaelic) represents /d/.

but are taken to be from MEng. brandreth by Marstrander (1915a, 121).

While MEng. brandreth itself derives from ON brandreið (OED^˄), the short unstressed vowel of EG brannraḋ, and so Ir. brannradh, suggests a derivation from Middle English rather than Old Norse. SG branndair, 

Shaw’s (1780) brannradh ‘trivet’ is taken to be a borrowing from Lhuyd (1707: Ir. bránnradh ‘pots’).

on the other hand, is more likely to derive from Scots brander, brainder ‘gridiron’ etc. [′brɑn(d)ər, ′brendər] (SND^˄), as suggested by MacBain (1911) and MacLennan (1925), 

And perhaps implied by HSS (1828).

but with the ending adapted to the Gaelic agent noun suffix -air -[aɾʲ], -[ɛɾʲ]. Armstrong (1825) lists brandair ‘gridirion’, which he ascribes to MacDomhnuill (1741); in fact MacDomhnuill gives braundair ‘gridiron or brander’ (p. 89), which seems to indicate that the stressed vowel in MacDomhnuill's own Gaelic was diphthongised and possibly that a connection with Scots brander was understood.

Armstrong also lists brandal, which he also ascribes to MacDomhnuill, but this has not been traced and may be the result of conflation by Armstrong of successive entries in MacDomhnuill: braundair ‘gridiron or brander’ and graidil, greidle ‘girdle’.