TOP OUT is a term used in many different contexts. In the context of a crossword puzzle, it can refer to two different solutions: MAX (3 letters) and PEAK (4 letters). MAX is an abbreviation for maximum, which means the highest or greatest amount or degree possible. PEAK is a noun that refers to the highest point or summit of a mountain or hill. Together, these two words can be used to describe reaching the highest point or level of something.