Etymology

The vocalism indicated by N ME forms with spellings in <a> and <o> comes from the ON, cp. hár, rather than the OE reflex hǣr, hēr (see Jordan-Crook §49, remark 2) of this common NWGmc n. (< PGmc *xēran, cp. OFris hēr, OS, OHS hār).

PGmc Ancestor

*xēran

Proposed ON Etymon (OIcel representative)

hár 'hair'
(ONP hár (2) (sb.))

Other Scandinavian Reflexes

Far hár, Icel hár, Norw hår, Dan hår, Sw hår

OE Cognate

hǣr, hēr 'hair'

Phonological and morphological markers

ON /ɑ:/ &lt; PGmc */e:/ (1)

Summary category

A1*c

Attestation

Spellings in <a> and <o> (OED's β) are characteristically N in ME.

Occurrences in the Gersum Corpus

Cl 1695; WA 227, 320, 854 etc.

Andersson (1695n) observes that the collocation with campe (n.) also occurs in Chaucer. Unlike Skeat, TPD interprets A MS reading <haris> (D <horez>) at WA 1009 as an instance of the v.  < OE hārian 'to become hoary or grey' (see their 1133n).

Bibliography

MED hēr (n.) , OED hair (n.) , HTOED , Bj. 90, de Vries hár (2), Mag. hár (3), Orel *xēran, Kroonen *hēra-, DOE hǣr, AEW hǣr