Cite the scanned version of the original dicionary like this:
Bosworth, Joseph. "cǽg-bora." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth. Ed. Thomas Northcote Toller. Oxford: Clarendon Press, 1898. 143.
.Add: one who has charge of the keys of a jail, jailor :-- Cǽgbora clavicularius. Wrt. Voc. i. 288, 45: ii. 17, 11. Sc̃s Heremus wæs cǽgbora in Róme, Shrn. 121, 23. [Cf. N. E. D. key-bearer.] Cf. cǽg-hirde.