A capital M in the margin of an entry is an abbreviation for the Latin word manerium, manor. The marginal abbreviation is found in circuits 3 and 6. In circuit 6, every rural holding was categorised as a manor, outlier or jurisdiction; but in circuit 3 only manors were accorded this treatment.
The marginal M has played a significant part in discussions over the meaning of the Domesday manor.
For the manorial structure of circuit 6, see F.M. Stenton, Types of manorial structure in the northern Danelaw (1910); and Dawn M. Hadley, The northern Danelaw: its social structure, c.800-1100 (2000); and for conflicting interpretations of the meaning of the term 'manor', see J.H. Round, 'The Domesday manor', English Historical Review, vol. 15 (1900), pages 293-302; John J.N. Palmer, 'The Domesday manor', Domesday studies, edited by J.C. Holt (1987), pages 139-54; and David Roffe, Domesday: the Inquest and the Book (2000).