Feudum

A fief (/ˈfiːf/; Latin: feudum) was the central element of feudalism and consisted of heritable property or rights granted by an overlord to a vassal who held it in fealty (or "in fee") in return for a form of feudal allegiance and service, usually given by the personal ceremonies of homage and fealty. The fees were often lands or revenue-producing real property held in feudal land tenure: these are typically known as fiefs or fiefdoms. However, not only land but anything of value could be held in fee, including governmental office, rights of exploitation such as hunting or fishing, monopolies in trade, and tax farms.

In ancient Rome a "benefice" (from the Latin noun beneficium, meaning "benefit") was a gift of land (precaria) for life as a reward for services rendered, originally, to the state. In medieval Latin European documents, a land grant in exchange for service continued to be called a beneficium (Latin). Later, the term feudum, or feodum, began to replace beneficium in the documents. The first attested instance of this is from 984, although more primitive forms were seen up to one hundred years earlier. The origin of the feudum and why it replaced beneficium has not been well established, but there are multiple theories, described below.

The most widely held theory is put forth by Marc Bloch that it is related to the Frankish term *fehu-ôd, in which *fehu means "cattle" and -ôd means "goods", implying "a moveable object of value." When land replaced currency as the primary store of value, the Germanic word *fehu-ôd replaced the Latin word beneficium. This Germanic origin theory was also shared by William Stubbs in the nineteenth century.

...
Wikipedia