Geán-bōc

According to the Old English Dictionary:

geán-bōc

f. A duplicate charter :-- Geánbōc to Beonetleáge, C. D. vi. 177, 24. Geánbēc (printed Cean-) intō Glēweceaster, iii. 208, 25. Ðās gēnbēc hȳrad intō Wincescumbe, 256, I : C. D. B. iii. 338, 20. gean-boc