sweorcan
This might be just a supplemental entry adding to an entry in the Main Volume.
Related §§ in Wright's OE Grammar:
In the OE text, the length is:indicated by acute accentsindicated by macronsnot indicated.
sweorcan
. I. AddÞonne se man sceal sweltan, þonne swyrceð him fram þæs húses hrófe ðe hé inne bið, Verc. Först. 108, 1. Hé ásende þeóstru and swearc misit tenebras et obscuravit, Ps. L. 104, 28. I a. to grow black :-- Sweorcan and sweartian nigrescere, Chrd. 96, 10.
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.