Who could own land in the feudal system?

The feudal system was based on the king and the Church owning every inch of land. Everyone else was allowed to holdportions of it, and have sub-tenants holding land from them, in return for services and payments of various kinds.

This is the reason for the compilation of Domesday Book, so that the newly-crowned king William I could calculate the value of all his land and the expected income from the entire kingdom.

The Word "tenant" comes from Latin teneo, I hold. The cottars at the very bottom of the social ladder might hold about 12 to 15 acres of land from a knight (lord of the manor); a freeman might hold 60 acres and each would pay in work, in rents and customary services. The knight might hold all his manors from a higher-ranking knight in return for military service and the higher-ranking knight might hold his lands from an Earl, who held huge areas of land from the king.