System

The term system is most frequently used by Humans as shorthand for planetary system, the grouping of all planetary bodies and other satellites that orbit a given star. The planets of a particular planetary system are by default given the name of the star itself followed by a roman numeral, ordered beginning with I as the innermost planet. Satellites of those planets are designated with an Arabic numeral matching the planet they orbit followed by a lowercase letter starting with a for the innermost moon. Less frequently, system may refer to a star system, a group of multiple stars which are impacted by one another's gravity and proximity.