This might be just a supplemental entry adding to an entry in the Main Volume.
á-dwínan
.Add :-- Ðá nigontýne geár gedóð ðæt án dæg mid ðǽre nihte ádwínð, and swylce ic swá cweðe tó náhte gewyrð, Angl. viii. 308, 32. Áduínendan tabida, Txts. 104, 1044.
Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "á-dwínan." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 9.