"(1) A reversionary interest is any future interest left in a transferor or his successor in interest.


"(2) A reversion is any reversionary interest which is not subject to a condition precedent.


"(3) A possibility of reverter is any reversionary interest which is subject to a condition precedent." Restatement (First) of Property § 154 (1936).

"Sometimes reversionary interests are indefeasibly vested, as for example, when A, having complete property in a thing transfers an interest therein measured in duration by the life of the transferee (see Illustration 1). Sometimes a reversionary interest is defeasibly vested, as for example, when a transferor, who has an estate in fee simple absolute, transfers an estate for life plus a remainder in fee simple absolute subject to a condition precedent (see Illustration 6). Of this type also is the reversion left in a transferor, who, having had an estate in fee simple absolute, transfers an estate in fee tail. The tenant in tail by exercising his power to transfer an estate in fee simple absolute (see § 79) can defeat the reversion.

Sometimes a reversionary interest is subject to a condition precedent, as for example, when the created interests can exhaust the full interest had by the transferor prior to his transfer, but upon the occurrence of a stipulated event, will sooner end, leaving a balance to be enjoyed by the original transferor (see Illustrations 2, 3 and 7). Reversionary interests of the first two types are designated reversions, while reversionary interests of the third type are designated possibilities of reverter. These differentiations of future interests into categories “indefeasibly vested,” “defeasibly vested” and “subject to a condition precedent” are of greater importance as to remainders than as to reversions." Restatement (First) of Property § 154 cmt. e (1936).

Illustrations:

2. A, owning Blackacre in fee simple absolute, transfers Blackacre “to B for life, remainder to C and his heirs, but if C dies in the lifetime of B, then the estate hereby granted to C is to end and the land is to revert to A and his heirs.” A has a reversionary interest in Blackacre.

3. A, owning Blackacre in fee simple absolute, transfers Blackacre “to B and his heirs until Gloversville is incorporated.” A has a reversionary interest in Blackacre.

7. A, owning shares and bonds worth $150,000, transfers them “to B as trustee to hold for the life of C, paying the net income to C to the extent of $4,000 per year, and dividing the balance of the net income between D and E, children of C, remainder on the death of C, to the then surviving children of C.” A has a reversionary interest in the shares and bonds. Restatement (First) of Property § 154 illus (1936).

On the other hand, several hundred reported cases show up in Westlaw in which the search term is "contingent reversion."