, þel-fæstenn, es; n. A fortress of planks (Noah's ark) :-- Nolde seó culufre under salwed bord syððan ætýwan on þellfæstenne, Cd. Th. 89, 17; Gen. 1482.
Cite the scanned version of the original dicionary like this:
Bosworth, Joseph. "þel-fæsten." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth. Ed. Thomas Northcote Toller. Oxford: Clarendon Press, 1898. 1046.