The word feudal does not appear in Domesday Book, or indeed in any medieval source. Even the word fief, from which feudal and feudalism are ultimately derived, does not have its classical feudal meaning in Domesday. Feudal and feudalism are terms coined by later ages to describe aspects of a past society. Both terms are used with a wide variety of meanings, so wide, it is sometimes claimed, as to make them meaningless and a obstacle rather than an aid to understanding.
However, in the particular circumstances of the Norman Conquest, one strand of meaning has some validity. 'Feudal' meaning a 'hierarchy of property rights' is well-attested in Domesday Book. During the twenty years after the Conquest, William the Conqueror redistributed the bulk of the land in lay hands among his magnates, or tenants-in-chief as they are conventionally known. They rewarded their followers, many of whom redistributed part of their gains among their own dependants; every landowner knew from whom he had received his land and to whom he owed the service for that land. The hierarchy created by this process of subinfeudation is emphasised by the structure of Domesday Book which, for this reason, has sometimes been called 'a blueprint for feudalism'. For a few generations, feudalism in this sense had some reality. The Latin kingdom of Jerusalem was feudal in the same sense, and for the same reason.
On fiefs and feudalism, see Sir Fredrick Pollock and F.W. Maitland, The history of English law before the time of Edward I (second edition, 1898); and Susan Reynolds, Fiefs and vassals: the medieval evidence reinterpreted (1994); on military quotas, J.H. Round, Feudal England (1895); and John Gillingham, 'The introduction of knight service into England', Anglo-Norman Studies, vol. 4 (1982), pages 53-64; 181-87.