A double star is a pair of stars that orbit each other. The term 'double star' can also refer to a binary star system, which is two stars that are gravitationally bound and orbit around their common center of mass. The crossword solution for the term double star is Vega, which is the brightest star in the constellation Lyra and the fifth brightest star in the night sky. Vega is a blue-white star and is part of a binary star system, making it a double star.