In the feudal era, a manor was a deeded estate.
So, a person might be deeded the City of Portland Maine.
He would then be responsible for the welfare of the people of Portland and in return, the people of Portland would pay taxes and work on the land owned in Portland.
A key difference would be that today, we own the land we live and work on (unless we rent) and pay taxes to the Government instead of a feudal lord.