The term 'fleurs-de-lis' is a French symbol of royalty and is often used in heraldry. It is composed of two elements: the LILY, which is represented by the letter 'L' in the crossword solution, and irides, which is represented by the letters 'IRIDES'. The LILY is a flower that has been associated with royalty since ancient times, while irides is a term used to describe the rainbow-like colors of certain flowers. Together, these two elements form the fleurs-de-lis, a symbol of power and prestige.