affirmative easement
affirmative servitude
positive easement
positive servitude

Likewise, it is almost always an affirmative easement, that is, one that permits a person to do something.

In most U.S. jurisdictions, a prescriptive easement can only be determined for an affirmative easement not a negative easement.

For example, an affirmative easement might allow land owner A to drive his cattle over the land of B. A has an affirmative easement from B.

An affirmative easement is the right to use another's property for a specific purpose, while a negative easement is the right to prevent another from performing an otherwise lawful activity on their property.