The crossword solution for the term 'Epitome of Lightness' is AIR, which is a three letter word. AIR is a common gaseous substance found in Earth's atmosphere and is composed of nitrogen, oxygen, and other gases. It is the most abundant gas in the atmosphere and is essential for life on Earth. AIR is also used to describe a light, airy feeling or quality, which is why it is the perfect solution for the term 'Epitome of Lightness'.