The crossword solution for the term 'Cause to Continue Indefinitely' is EON, which is a three-letter word. EON is a term used to refer to an indefinite or immeasurably long period of time. It is often used to describe geological time periods, such as the Precambrian EON, which lasted from 4.6 billion years ago to 541 million years ago. In more general terms, EON can be used to describe any period of time that is incredibly long and seemingly without end.