What are Gender Systems?
Gender systems are a structure within a community or society that serves to define genders, gender roles, and how those interact and generally define people's behaviors within said society or community. Typical societal gender systems include a masculine and/or male and feminine and/or female role, with many also including either a both or neither role (some also include both). The most commonly talked about gender system would be the Western Binary, which is made up of man and woman, which are respectively connected to masculinity/malehood and femininity/femalehood.
MOGAI Gender Systems
Basic Definition
A general definition of gender systems within MOGAI is "to define gender identity, alignment, or presentation. These are usually non-binary genders or xenogenders. Systems usually have an aesthetic or theme that it follows."1
Expanded Definition
Within the MOGAI community, gender systems generally work somewhat differently than gender systems outside of MOGAI. Rather than defining the typical male and/or masculine female and/or feminine, and occasional both and/or neither, and gender roles, they're generally made up of genders related to similar things or connected by a central theme, without masculinity, femininity, etc. being main elements. If those are part of the systems in any way, there's generally something else involved as well, rather than the genders solely being related to typical gender roles and aspects.
There are some outliers to that, such as the Galactian Alignment System, Alloy Alignment System and a few others. These outliers are primarily made up of masculine, feminine, male, female, etc. with some having an added xenic element and xenic genders. Within MOGAI, gender systems can also be called gender families or gender groups.