Side system

(Namespace: plural glossary)

Type of term Part of the structure of a system
Synonyms or near-synonyms Layer, subsystem
Antonyms or near-antonyms None

A side system is a self-contained grouping of headmates in a greater system. It is the same thing or nearly the same thing as a subsystem, except possibly with the connotation that side systems are hierarchal siblings as opposed to one being a hierarchal descendant of the other(?)