A more thorough explanation:

Superficiarius

In ancient Roman law, a superficiarius was a person who had the right to own a building on public or private land, but had to pay an annual rent for it. This right was hereditary and could be sold or transferred to someone else.

An example of a superficiarius would be a person who built a house on public land and paid an annual rent to the government for the right to use the land. Another example would be a person who inherited the right to a building on private land and paid an annual rent to the landowner.

These examples illustrate how a superficiarius had the right to use a building on land that they did not own, but had to pay for that right. It was a way for people to have access to land and buildings without having to buy them outright.