The term 'State of Serenity' can be defined as a peaceful state of mind. It is often associated with relaxation, contentment, and tranquility. The crossword solution for this term is 'PEACE, ' which is a five-letter word that is used to describe a state of harmony between people or groups. This term is often used to describe a situation in which there is no conflict or disagreement. In other words, it is a state of calmness and serenity.