á-dún
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.
á-dún
-dúne (-a). Add:1. á-dún Feall nú ádún, Hml. Th. i. 166, 19: Hml. S. 11, 108. Hé ofdrǽd slóh ádún, 23, 718. 2. á-dúne (-a) Feól hé ádúne, Hml. Th. 1, 316, 29. Hí lédon heora wǽpna ádúne, Hml. S. 29, 171. Clif áscoren rihte ádúne, 31, 316. Heáfod ádúne gewended, Bl. H. 173, 4. Ásend ðeh ádúna (deorsum ), Lk. L. 4, 9. Cumað ádúne of heofonum tácn, Wlfst. 137, 12. Hé his gesyhða ádúna on eorðan besette, R. Ben. 31, 8. Úre blód fleóð tó úrum fótum ádúne, Hml. S. 11, 191. Doppettan ádúne tó grunde, Hml. Th. ii. 516, 7. v. of-dúne.
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A Combined List of Abbreviations.