The crossword solution for the term 'WHAT'S LAST' is END, which is a three-letter word. END is often used to refer to the conclusion of something, such as the END of a movie or the END of a book. It can also be used to refer to the final stage of a process, such as the END of a project or the END of a journey. In this context, it could be interpreted as referring to the last thing that happens in a particular situation.