A more thorough explanation:

Definition: Estate in remainder refers to a future interest in a third person, who is not the creator of the estate, its initial holder, or their heirs. This person is intended to take over the property after the natural termination of the preceding estate. For example, if a grant is “to A for life, and then to B,” B's future interest is a remainder. If there is only one preceding estate and the remainder vests on that estate's expiration, the remainder is also termed an executed estate.

Examples:

• “To A for life, and then to B” - B's future interest in the property is a remainder.
• “To A for life, and then to A's children” - A's children have a contingent remainder in the property, as their interest is subject to the condition precedent of surviving A.
• “To A for life, and then to B if B graduates from college before A dies” - B's interest in the property is a contingent remainder, as it is subject to the condition precedent of graduating from college before A's death.

The examples illustrate how a remainder is a future interest in a property that arises in a third person after the natural termination of the preceding estate. The type of remainder (vested, contingent, defeasible, etc.) depends on the language used in the grant and any conditions or contingencies attached to the interest.