v1.0
Published 01/10/24
pònair f. [ˈpʰɔ̃ːnaɾʲ], [ˈpʰɔ̃ːnɛɾʲ], 
Dieckhoff 1932: (Glengarry) [pòːnerˈj]. Kirk 1702 (in Campbell 1938, 90), whose use of lengthmarks is inconsistent, gives panair ‘beans’, but first-syllable a is more likely a copying or typesetting error than an authoritative representation of the stressed vowel.
[ˈpʰɔ̃ːnəɾʲ], sometimes with final non-palatal -[ɾ], 
Cf. Wentworth 2003: (Gairloch) [pʰɔ̃ːnər].
‘bean or (coll.) beans’, gen. pònarach or pònaire; cf. Ir. pónair, pónaire, pónra, Mx poanrey, 
Mx [poːnsə],[pǫnsə] (Broderick 1984 II, 351; cf. Kneen 1978, s.v. bean: (pawnra, pawnza)). Jackson (1955, 124) refers to the development of nr in Manx, for reflexes of which see Broderick 1984 III, 111–12.
EG pónair.
Bugge (1912, 303) and MacBain (1911) derive SG pònair from ON baun f. ‘bean’.
MacBain cites Stokes, ‘Celt[ic] Dec[lension’, Transactions of the Philological Society 1885–1886, 97–201], but the reference has not been traced.
Marstrander (1915a, 59, 71, 96) provides an explanation for the presence of a second syllable in EG pónair by suggesting a derivation from ON baunir pl.; so MacLennan (1925), de Vries (1962), Greene (1978, 121), Stewart (2004) and McDonald (2009, 340).
Initial ON b- can normally be expected to yield EG /b/ (e.g. ON boða obl. > SG bodha, q.v.), but, although /p/ sometimes develops from /b/, e.g. EG bláesc > Northern Ir. blaosc, Mx bleayst, but Munster Ir. plaosc, SG plaosg (O’Rahilly 1976, 149), impetus for the change in this instance 
There is variation in Rathlin Ir. [pɔːnir], [pɔːnər], [bɔːnir] and [bɔnir] (sic) (Holmer 1942, 223).
may have come from Ir. pis and SG peasair, see below. ON au yields EG, Ir. and SG long ō regularly, e.g. ON skaut nt. > SG sgòd, q.v. However, the borrowing of plural ON baunir as singular EG pónair is strange at first sight, but is perhaps mitigated by the fact that pónair was used as a collective noun, perhaps in the context of beans being bought and sold in bulk, and because the word may have been felt to contain or contain the equivalent of the collective suffix -ar (Thurneysen 1976, 170), e.g. EG clochar ‘collection of stones, stony place’ (< cloch ‘stone’) and búar ‘cattle’ (< bó ‘cow’). EG pónair has possibly influenced the development of SG peasair f. and Ir. peasair f. as collective nouns from Eng. pease, although the Irish word occurs only in the sense ‘vetch’ (Ó Dónaill 1977; contrast Ir. pis ‘pea; peas’ < Lat. pisum (eDIL˄)). ON baunir seems to have been borrowed into Gaelic as a fem. i̯ā-stem, but which has in general become a guttural stem (cf. Thurneysen ibid., 204), hence SG (gen.) pònarach, cf. SG (gen.) peas(a)rach.
On the basis that a loan from ON baun sing. to EG *pón sing. does not occur, then, it might be argued that ON baunir pl. was borrowed as EG pónair sing. via an association with the native collective suffix -ar (with [ə]), with pónair itself perhaps a model for SG and Ir. peasair.
Scots peaser ‘small marble’ (SND˄, s.v. pease) is probably an independent Scots formation.
However, the supposed suffix has evidently been confused to some extent with the Early Gaelic suffix -óir: with unstressed [a] in Donegal (Sommerfelt 1949, 235: [poːnar´]) and with unstressed [a] or [ɛ] commonly in Scottish Gaelic; 
See the transcriptions, above. For SG peasair, Dieckhoff (1932) gives unstressed [ɛ], but McAlpine (1832) and MacLennan (1925) [i].
with the Early Gaelic suffix -(a)ire: in Irish pónaire; 
Ó Dónaill 1977.
and with the Early Gaelic collective suffix -raḋ: Ir. pónra, 
Earlier *pónradh, cf. 1836 Cartronponragh (Cartún na Pónaire), Sligo G 65598 31149 (Bunachar Logainmeacha na hÉireann˄); cf. Ir ballra m. ‘members’, earlier ballradh.
which was borrowed as Mx poanrey ‘bean (Y Kelly 1866), beans (Broderick 1984 III, 111–12)’.
Lewin 2019, 149: Mx poanrey ‘bean(s)’ < [Ir.] póna(i)r, pónra.
Demand for a distinction between singular ‘bean’ and plural ‘beans’ has given rise to SG (pl.) pònairean, 
E.g. (Gairloch) (sg.) pònar ‘bean; beans’, (pl.) pònairean ‘beans’ (Wentworth 2003, s.v. bean) with the consequence that pònair is sometimes considered to be a singulative only (AFB˄). Contrast the usage (Glengarry) spuilgein pònair ‘one bean’ (Dieckhoff 1932, s.v. pònair).
cf. Ir. (sg.) pónaire ‘bean; beans’, (pl.) pónairí (Ó Dónaill 1977).