31 CFR § 802.226 - Lease.
(a) The term lease means an arrangement conveying a possessory interest in real estate, short of ownership, to a person for a specified time and in exchange for consideration. This term includes subleases and assignments in whole or part.
(1) Example 1. Foreign person A enters into an arrangement with a neighbor that allows the foreign person to use a private road running across the neighbor's land. The road will remain owned by the neighbor following the arrangement. The neighbor will also retain physical possession of his land despite the foreign person having permission to traverse the land while using the road. The arrangement does not convey a possessory interest in real estate. Assuming no other relevant facts, the foreign person has not entered into a lease.
(2) Example 2. Same facts as the example in paragraph (b)(1) of this section, except that the foreign person's arrangement with the neighbor gives the foreign person the exclusive right to occupy a portion of the neighbor's land and attach fixtures to the surface, in exchange for a fee for a specified period of time. The foreign person can unilaterally adjust, remove, and make other changes to the fixtures. The foreign person has entered into a lease.