Etymology

Always derived from the ON n. represented by OIcel tóm 'emptiness; (metaphorically) leisure'; the n. is only attested in Norse, but derives from a more widespread Gmc adj. *tōma- (cp. OIcel tómr 'empty, free', OE tōm 'free from, empty', OS tōm 'single').  Bj. also notes the sense and distribution of the ME word as points in favour of its Scandinavian origin.

PGmc Ancestor

*tōm-

Proposed ON Etymon (OIcel representative)

tóm 'emptiness; (metaphorically) leisure'
(ONP tóm (sb.))

Other Scandinavian Reflexes

OE Cognate

cp. tōm (adj.) 'free from, empty'

Phonological and morphological markers

Summary category

C1c

(C3c)

Attestation

MED has widespread citations from the 14c., but esp. frequent in N texts. In later use in Scots (OED).

Occurrences in the Gersum Corpus

Pe 134, 585; Cl 1153; Pat 135; Erk 313

Bibliography

MED tōme (n.) , OED toom (n.1) , HTOED , Bj. 256, de Vries tóm, Orel *tōmaz, Heid. tōma-