Little
A little is a headmate that behaves or otherwise feels like they are a young age. This often approximately caps at age twelve, but may vary personally between systems based on their body's age. A little may behave similarly to, feel like, or (internally) look like a child, or any combination.
"Being little" may also be used by age sliders or similar headmates that experience younger ages temporarily to refer to their regressed state.
Alternate terms for little include: Middle and Teen can be used interchangebly for alter ages thirteen to seventeen. Alters eighteen or older would be considered "Big" in this case.