on-þræc
This might be just a supplemental entry adding to an entry in the Main Volume.
In the OE text, the length is:indicated by acute accentsindicated by macronsnot indicated.
on-þræc
AddÞá ofseáh hé ðá hǽðenan ferian án líc tó eorðan mid anþræcum gehlýde, Hml. Th. ii. 508, 17. Scuton hí intó ðǽm anðræcum cyle prosiliebant in medium rigoris infesti, 350, 11. Seó dene wæs weallende mid anðræcum lígum, on ánre sídan (cf. unum latus flammis feruentibus nimium terribile, Bd. 5, 12), 350, 7. Tengdon þá hǽþenan mid andþrecum wǽpnum tó þám ǽwfæstum heápe, Hml. S. 28, 67.
This is a supplementary entry with editorial changes to an entry in the main volume of the dictionary. Look under the 'Possibly connected entries' below, or for the same headword in the list to the left.

A Combined List of Abbreviations.

Abbreviation not recognized. See:

A Combined List of Abbreviations.