A more thorough explanation:

Substantial possession is when someone has de facto control over something that they intend to control. It can refer to actual occupancy or use of real property.

For example, if someone moves into a house and starts living there, they have substantial possession of the property. They are in control of the property and intend to keep living there.

Another example is if someone starts using a piece of land for farming. They have substantial possession of the land because they are using it and intend to keep using it for farming.

Overall, substantial possession means having control over something and intending to keep that control. It is an important concept in property law.