As used in this chapter: “Land” is a three-dimensional concept and includes parcels with upper or lower boundaries, or both upper and lower boundaries, as well as parcels extending ab solo usque ad coelum. Parcels of airspace constitute land within the meaning of this chapter. Any requirement in this chapter of a legally sufficient description shall be deemed to include a requirement that the upper and lower boundaries, if any, of the parcel in question be identified with reference to established data. “Obligee” means any person or entity to whom a residential ground rent is owed. “Obligor” means one or more individuals who are obligated to pay a residential ground rent. “Residential ground rent” means a rent or charge paid for the use of land, whether or not title to such land is transferred to the user, or a lease of land, for personal residential purposes, (i) which is assignable by the obligor without the obligee’s consent; (ii) which is for a term in excess of 15 years, including any rights of renewal at the option of the obligor; (iii) where the obligor has a present or future right to terminate such ground rent and to acquire the entire interest of the obligee in the land by the payment of a determined or determinable amount; and (iv) where the obligee’s interest in the land is primarily a security interest to protect his right to be paid the rent or charge.