The crossword solution for the term SUN-RELATED is SOLAR, which is a five letter word. SOLAR energy is energy from the sun that is converted into thermal or electrical energy. SOLAR power is becoming increasingly popular as an alternative energy source due to its clean and renewable nature. SOLAR energy can be used to generate electricity, heat water, and even power cars. SOLAR panels are used to capture the sun's energy and convert it into usable electricity. SOLAR energy is also used to power satellites and spacecrafts.