The crossword solution for the term 'SOLO FOR SILLS' is ARIA, which stands for a self-contained piece of music for a single voice. An ARIA is typically found in an opera or cantata and is usually accompanied by an orchestra. It is usually a lyrical piece that expresses the emotions of the character singing it. The term 'solo for sills' refers to a solo ARIA, which is sung by one singer without any accompaniment.