The term 'ALL THERE IS' can be represented by four different crossword solutions: UNIVERSE (8 letters), COSMOS (6 letters), THATS (5 letters), and ISTHAT (6 letters). The word UNIVERSE refers to the entirety of space and time, including all matter, energy, and phenomena. COSMOS is a synonym for UNIVERSE, and is often used to refer to the physical UNIVERSE, as opposed to the spiritual or metaphysical. THATS is an abbreviation of 'that is, ' which is used to indicate that something is true or correct. ISTHAT is another way of saying 'is that so, ' which is used to express surprise or disbelief. All four of these words can be used to describe the concept of 'ALL THERE IS, ' which is the totality of existence.