Ahh - the feudal system, which operated in Scotland till 2004.
A long story but short story is - a form of land tenure whereby an estate owner ['feudal superior'] grants a perpetual right to a tenement of land, with or without house, to someone [the 'feuar'] in return for originally military service later commuted to a financial payment ['feu duty']. The superior could retain certain rights if he wished eg type of building, mineral rights underneath the soil, maintenance of a common area & these were detailed in a [chronological order of historical terms] Feu Charter, Feu Contract or Feu Disposition. Up to a certain date the superior had to be informed of change of ownership whether it was by inheritance or purchase but this was mainly to keep track of who was due to pay the annual money. No new feus could be created after 2004 - Scotland retaining the feudal system for centuries longer than any other European country. Apart from leases all new land tenure is now outright, like English freehold.
A comparison to English land tenure could be called a perpetual lease.
That's a very simple overview which I & others here could expand on at length
. There's a bit here
https://en.wikipedia.org/wiki/Scots_property_lawbut try an online search too.
