Yesterday's Tomorrow is a phrase that refers to the idea of living in the past and not looking forward to the future. It is often used to describe someone who is stuck in their ways and unwilling to change or adapt. The term can also be used to describe a situation where something that was once thought to be the future has become outdated. The crossword solution for this term is 'Today', which is a reminder that we should live in the present and look forward to the future.