Etymology

Always derived from ON, cp. OIcel þrennr, þrinnr ‘triple, threefold’, with an etymology mirroring ON tvennr, tvinnr ‘twofold, double’: PGmc *þrizna- < PIE *tri-s-no- (a formation on the *tri- ‘three’ root). Assimilation of /zn/ > /nn/ can be explained by other means than ON loan, e.g. an unrecorded native OE *þrinn- < PGmc *þrizna which might have evolved by analogy with (ge)twinn (see twynne) (SPS 106).

PGmc Ancestor

*þrizna-

Proposed ON Etymon (OIcel representative)

þrennr ‘triple, threefold’
(ONP þrennr (adj.))

Other Scandinavian Reflexes

Far trinnur, Icel þrennur, Norw trinn, ODan thrænnæ, Dan trende, OSw þrænni, þrinni, Sw trenne

OE Cognate

Phonological and morphological markers

[ON consonant cluster assimilation] (possibly diagnostic)

Summary category

B1c

Attestation

After a single occurrence of a ðrinna in late OE, in LawIIIAtr (see SPS 328, Hofmann 1955: §265, Peters 1981a: 98), in ME from Orrm onwards in N and E only. On the use of this form metri causa see Putter and Stokes 2007: 484, Dance 2013: 55.

Occurrences in the Gersum Corpus

Gaw 1868; Cl 606, 645, 1727

On the sense of Gaw 1868, see Emerson 1922: 399.

Bibliography

MED thrin (num.) , OED thrin, thrinne (adj. and n.) , HTOED , Dance þrynne, Bj. 172-3, SPS 105–6, 328, de Vries þrennr, þreðr, þrinnr, Mag. þrennur, Jóh. 457, Orel *þrixnaz, AEW ðrinna