Multi star systems are what scientists call systems of stars that are composed by 3 or more stars, this is more than two stars, most of the multi stars systems have only three stars this is because the logistics and forces necessaries to create a system that has 4 or more stars are really complicated and less likely to occur.
Mizar is a quadruple or quaternary star system. When there is more than two stars, it is called a star system or multiple star system or stellar system. Depending on the number of stars, they are also called a triple, quadruple or quintuple star system or trinary, ternary, quaternary, quintenary, sextuple, sextenary, septuple or septenary star system.
