Etymology

cp. OIcel fjall, fell ‘mountain’ < PGmc *felz- with assimilation of /ʀ/; cp. the Ablaut variant *falis- behind OHG, OS felis ‘rock, cliff’ 

PGmc Ancestor

*felz-

Proposed ON Etymon (OIcel representative)

fjall, fell ‘mountain’
(ONP fjall (sb.), fell (sb.))

Other Scandinavian Reflexes

Far fjall, Icel fjall, Norw fjell, Dan fjeld, fjæld, Sw fjäll

OE Cognate

Phonological and morphological markers

ON consonant cluster assimilation

Summary category

A1bc

Attestation

Only a handful of examples in MED, nothing earlier than c. 1400; predominantly but not exclusively N and E (see further  Hug 1987: 185-7, 190-219), including in place-name usage (see EPNE, Elliot 1984: 81-2,90-1); in N dial usage.

Occurrences in the Gersum Corpus

Gaw 723; WA 1211, 4046

The A MS of WA reads <hillis> at 1211.

Bibliography

MED fel (n.2) , OED3 fell (n.3) , HTOED , HTOED , EDD fell (sb.2), Dance felle, Bj. 170, de Vries fjall (1), Mag. fjall (1), Bj-L. fjell, Orel *felzan ~ *fel(e)zaz, Kroonen *fel(e)sa-, EPNE fjall, fell