The term 'THAT's So True' is often used to express agreement or approval. The two crossword solutions for this term are 'AMEN' and 'IAgree'. 'AMEN' is a Hebrew word meaning 'so be it' and is commonly used in religious contexts. It is also used to express agreement with a statement or sentiment. 'IAgree' is a more modern term, derived from the phrase 'I agree', which is used to express agreement or acceptance of an idea. Both terms are used to express agreement or approval of a statement or sentiment.