In the feudal system the demesne (pron.: // di-MAYN; from Old French demeine ultimately from Latin dominus, "lord, master of a household") was all the land, not necessarily all contiguous to the manor house, which was retained by a lord of the manor for his own use and support, under his own management, as distinguished from land sub-enfeoffed by him to others as sub-tenants. The system of manorial land tenure, broadly termed feudalism, was conceived in Western Europe, initially in France but exported to areas affected by Norman expansion during the Middle Ages, for example the Kingdoms of Sicily, Scotland, Jerusalem, and England.
Royal demesne 
In English common law the term ancient demesne referred to those lands that were held by the Crown at the time of the Domesday Book. Immediately following the Norman Conquest all land in England was claimed by the king as his absolute title by allodial right, being the commencement of the royal demesne. The king made immediate grants of very large parcels of land under feudal tenure from this demesne, generally in the form of feudal baronies. The land not so enfeoffed thus remained within the royal demesne, for example royal manors administered by royal stewards and royal hunting forests. It was from the income produced by these manors retained in the royal demesne that the king financed his administration, until the advent of taxation. Manors in the royal demesne were let out at "farm" to the sheriff of each shire in which they were located. Thus in return for an annual fixed payment made into the Exchequer, the sheriff was free to extract and retain whatever additional revenue he was able from the land "farmed", which amount was by design considerably greater than the "farm". The royal demesne could be increased, for example, as a result of forfeiture where a feudal tenure would determine and revert to its natural state in the royal demesne. During the reign of George III, Parliament appropriated most of the royal demesne, in exchange for a fixed annual sum, called the Civil List. The position of the royal estate of Windsor, still owned by the monarch and never alienated since 1066, may be a rare remnant of the royal demesne.
Lord's waste 
Later development 
Initially the demesne lands were worked on the lord's behalf by villeins or by serfs, who had no right of tenure on it, in fulfillment of their feudal obligations. As a money economy developed in the later Middle Ages, the serfs' corvée came to be commuted to money payments. With the advent of the Early modern period, demesne lands came to be cultivated by paid labourers. Eventually many of the demesne lands were leased out either on a perpetual (i.e., hereditary) or a temporary renewable basis so that many peasants functioned virtually as free proprietors after having paid their fixed rents. In times of inflation or debasement of coinage, the rent might come to represent a pittance, reducing the feudal aristocrat to poverty among a prosperous gentry. Demesne lands that were leased out for a term of years remained demesne lands, though no longer in the occupation of the lord of the manor (see, for example, Musgrave v Inclosure Commissioners (1874) LR 9 QB 162, a case in which the three judges of the Queen's Bench Divisional Court and everyone else concerned assumed without argument that farms which were let by the lord of the manor were part of the lord’s demesne land).
Derivative usage 
Since the demesne surrounded the principal seat of the lord, it came to be loosely used of any proprietary territory: "the works of Shakespeare are this scholar's demesne."
The term has also become synonymous with a park in many places, for example in Moira, County Down.
- Demesne is a variant of domaine with an unetymological s inserted. See http://dictionary.reference.com/search?r=2&q=demesne, http://cdict.giga.net.tw/q/demesne; Cassell's Latin Dictionary, Marchant & Charles
- See TheFreeDictionary definition of Manor: http://legal-dictionary.thefreedictionary.com/Manor