A binary or multiple star system whose total brightness varies on a regular cycle because the orbital motion of the member stars causes them to pass one in front of another as viewed from Earth. If the two stars in an eclipsing binary are of unequal luminosity, the light curve displays a primary minimum at A when the dimmer star passes in front of the brighter one, and a secondary minimum at C when the opposite occurs. The best-known example of an eclipsing binary is Algol.