(a) As used in this title, the term "realty" or "real estate" means:

(1) All lands and the buildings thereon;

(2) All things permanently attached to land or to the buildings thereon; and

(3) Any interest existing in, issuing out of, or dependent upon land or the buildings thereon.

(b) The property right of the owner of real estate extends downward indefinitely and upward indefinitely.