ge-mengednys
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.
ge-mengednys
AddNis ná gerunnen tógædere seó godcundnys and seó menniscnys, ac seó godcundnys is ymbscrýd mid þǽre mennisc-nysse, swá þæt þǽr nys náðor gemencgednys ne tódál, Hml. Th. ii. 8, 7.
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.