The term 'THAT PROVES IT!' can be broken down into three crossword solutions: AHA (3 letters), QQED (4 letters), and IRESTMYCASE (11 letters). AHA is an interjection used to express surprise, understanding, or recognition. QQED is an archaic form of the verb 'quod, ' which means 'SAID' in Latin. IRESTMYCASE is a phrase used to indicate that one has presented all the evidence they have and are ready for a conclusion to be drawn. Together, these three solutions form the phrase 'AHA, quod SAID, I rest my case!' which is used to emphasize that one has presented all the evidence they need to prove their point.