Latin, saca et soca.
Full jurisdiction implied that the lord held full jurisdictional rights, including the privilege of receiving fines for various trespasses. Lords with full jurisdictional rights would have held bookland and have recognised no lord but the king. Before the Conquest, these would have been royal thanes.
It has been argued that such thanes were often the predecessors of Norman tenants-in-chief, their estates forming the core of post-Conquest baronies, providing a significant element of continuity between Anglo-Saxon and Norman landholding structures.
For this thesis, see David Roffe, 'From thegnage to barony: sake and soke, title and tenants-in-chief', Anglo-Norman Studies, vol. 12 (1990), pages 157-76, and Domesday: the Inquest and the Book (2000); and for a different view on the break-up of Anglo-Saxon lordships, Robin Fleming, Kings and lords in Conquest England (1991).