Terms that describe who or what members are; such as "little" or "fictive." These are usually involuntary, but as with everything, differs from person to person.
Note: for terms more focused on jobs and duties, see system roles.
Age Slider: A person whose age varies, changes, or "slides" at different times. Is not the exact same as (SFW) Age Regression, but for some, they're considered the same thing.
[ID: A horizontal three-striped flag. Top to bottom, stripes are orange, purple, dark cyan. In the center is a simplistic pink cloud. ]
[ID: A horizontal three-striped flag. Top to bottom, stripes are purple, yellow, green. In the center is a red symbol of a person with their arms raised. ]
Lost Adult: Bodily in headspace, they look like an adult and identify with older ages, but mentally they think more like children. Someone with a "stunted" age, who physically grew up but mentally did not.
[ID: A horizontal three-striped flag. Top to bottom, stripes are seafoam, indigo, yellow. In the center is a dark red star. ]
Middle/Systeen: A teenage system member.
[ID: A horizontal six-striped flag. Top and bottom stripes are a dark, unsaturated purple. The middle four are, in order, dark pink, unsaturated pink, light yellow, light orange. ]
Aesthetive: an introject of an aesthetic personified (eg cottagecore, clowncore, vaporwave, etc)
[ID: A horizontal six-striped flag. Top and bottom stripes are dark green. The middle four are, in order, dark orange, light orange, light yellow, yellow-green. ]
Amitive: An introject of a member of another system, usually a system that is close to you but not always.
Factive: An introject of a real person.
Faitive/Fucktive/Fcktive: An introject in between a real person and a fictional source.
Fictive: An introject from a fictional source.