Reversion
Part of speech: noun
Definition: The action of reverting something. The action of returning to a former condition or practice; reversal. The fact of being turned the reverse way. The action of turning something the reverse way. The return of an estate to the donor or grantor after expiry of the grant. An estate which has been returned in this manner. The right of succeeding to an estate, or to another possession. The right of succeeding to an office after the death or retirement of the holder. The return of a genetic characteristic after a period of suppression. A sum payable on a person's death.
Lapse
Part of speech: verb
Definition: To fall away gradually; to subsideTo fall into error or heresyTo become void
Part of speech: noun
Definition: A temporary failure; a slip.A decline or fall in standards.A pause in continuity.An interval of time between events.A termination of a right etc, through disuse or neglect.(weather) A marked decrease in air temperature with increasing altitude because the ground is warmer than the surrounding air. This condition usually occurs when skies are clear and between 1100 and 1600 hours, local time. Strong convection currents exist during lapse conditions. For chemical operations, the state is defined as unstable. This condition is normally considered the most unfavorable for the release of chemical agents. See lapse rate.A common-law rule that if the person to whom property is willed were to die before the testator, then the gift would be ineffective.
Example sentence: I was 15 when Chernobyl happened, I've been vaguely thinking about it for most of my life. But somewhere around 2015, it occurred to me that I didn't know how it happened, which seemed like a pretty bizarre lapse in my understanding of the world and how it functions.