A more thorough explanation:

Indian title is a right of occupancy that the federal government grants to an American Indian tribe based on the tribe's immemorial possession of the area. This means that the government recognizes that the tribe has been using and occupying the land for a very long time, even before the arrival of Europeans.

Congress does not recognize tribal ownership of the land, only possession. This means that the tribe cannot sell or transfer the land to anyone else, but they can continue to use it for their own purposes.

For example, if a tribe has been using a particular area of land for hunting, fishing, and gathering for generations, they may be granted Indian title to that land. This means that they can continue to use the land for these purposes, but they cannot sell it or allow anyone else to use it without permission from the government.

An individual may also claim Indian title by showing that the individual or his or her lineal ancestors continuously occupied a parcel of land, as individuals, before the land was closed to settlers. This means that if someone can prove that their family has been living on a particular piece of land for a very long time, they may be granted Indian title to that land.

Overall, Indian title is a way for the government to recognize the long-standing connection that American Indian tribes have with the land, and to ensure that they can continue to use it for their own purposes.