Carcern-þeóstru

According to the Old English Dictionary:

e;

carcern-þeóstru

f. Prison-darkness, the darkness of the prison :-- Mistlice þreála gebyriað for synnum, bendas oððe dyntas oððe carcernþýstra, Ll. Th. ii. 278, 26. carcern-þeostru