I ran into ufustruct while reading Jefferson's papers. In that context, I think AI google etymology fits rather well.

The word usufruct has been used as a noun in English since the mid-1600s. It means the legal right to use and enjoy something that belongs to another person. The usufruct holder can use the thing as long as it doesn't destroy or injure it. However, the usufruct holder cannot sell, give away, or otherwise alienate it.

However, it came from Roman law, where usufruct was a temporary right to use and enjoy another person's property without altering the property's nature. The term comes from the Latin usus fructus, which means "use and enjoyment". Here are some key aspects of usufruct in Roman law (which I tend to think match Jefferson's use best);

Duration: Usufruct was usually for the lifetime of the usufructuary, but could be for a set term of years.

Rights: The usufructuary had the right to use the property and its fruits, such as livestock, rental payments, or actual fruits.

Responsibilities: The usufructuary was responsible for using the property in a good manner.

Property types: Usufruct could apply to land, buildings, slaves, and other property.

Creation: Usufruct could be created through a legacy, agreements, or stipulations.

Termination: Usufruct could be extinguished in various ways and revert to the owner.

Fruits: The owner usually owned the fruits produced by the property, but there were some exceptions. For example, the usufructuary and tenant only acquired the fruits after gaining control of them.

Return: At the end of the usufruct period, the usufructuary would return the property to the owner.

Thank you for the links, I skimmed a couple of your articles and bookmarked them to read. :) Me happy now, cause I like a good read.