Terminology!

Common/Main Terms

Use ctrl+f to find a term you're confused with, there's a lot here!

Singlet
A non-system; Someone without DID/OSDD. Not a slur, contrary to popular belief.

OSDDID
An portmanteau of DID and OSDD; means any medical system, meant to exclude endogenic systems (check the resources tab for more on them.)
Is typically used as pwOSDDID (people with OSDD DID)

System
Commonly used as another term for somebody with DID or OSDD1a/b. Refers to all of the alters within one body.

Subsystem
A "System within a system". Seperate internal groups with amnesia barriers between them.
May refer to a layer, which is a seperation of alters in a subsystem, based on headspace location or otherwise.
May refer to a cluster which is a group of alters in a subsystem. A cluster may be multiple similar alters, alters that all front together, or an alter with alters.

Splitting
The process of creating a new alter. Often caused by stress. (Not to be comfused with BPD splitting)

Fronting
Who's currently "driving". Whoever is controlling the body in the moment is the fronter.
Fronting can be split between multiple alters, which is refered to as Co-Fronting

Switching
When one alter leaves the front, and another takes their place. Switching places with another alter in the front, essentially. Characterized by dissociation

Blending
When two or more parts seem to merge together or overlap due to dissociation or switching.
Commonly refered to as blurring, but may have different connotations depending on the system.

Co-Concious
AKA CoCon. When an alter is aware of outside events at the time of them happening, but is not actively fronting. May or may not be giving passive influence to the fronters.

Innerworld
AKA Headspace. Where alters go when they're not fronting.

Polyfragmented
Often shortened to Polyfrag. Either means: 100+ alters, A system with many fragments, or A system that splits often, easily, and has complex splitting patterns. Often has a complex innerworld with multiple subsystems.

Pseudomemories
AKA Exomemories. False memories from one's delusions OR an introjects memories relating to their source; Memories that didn't happen to the body, but are still there.

Dissociation
A disconnect from reality; Can be broken down into different types.
Depersonalization: A detatchment from you're sense of identity and self; a detatchment from oneself through dissociation.
Derealization: A detatchment from your surroundings via dissociation.

Diagnosis
The process of getting recognized and treated for ones disorder; broken into 2 categories.
Self-DX: AKA Self Diagnosis, where one declares that they believe to have a specific disorder, usually after reasearch. (Note that Self-DX is completely valid.)
Prof-DX: AKA Professional Diagnosis, where a doctor declares ones disorder based on their symptoms. (Note that Prof-DX is a privilege based on race, sex, gender, and multiple other factors. They're also almost always subject to change.)

Dormancy
When an alter stops fronting, speaking or being co-con. They often also disapear from the innerworld. Like a coma, they can come back from dormancy but there is a high chance they never will. This happens when the brain finds that they've done their job, or are no longer needed in the system. Can happen due to stress.

Integration
When an alter "returns to the soup" as it were. They become one with the brain again. Their memories are typically shared with the rest of the headmates. A way of healing from a dissociative disorder. Must be purposefully or semi-purposefully done.

Fusion
When two or more alters fuse and become one.

Final Fusion
When a system becomes a singularity, all alters integrating or fusing into one.

Fracturing
When one alter becomes 2+ other alters.

Alter Roles/Terms

ANP
A medical term; Stands for 'Apparently Normal Part.' Deals with daily + social life.

EP
A medical term; Stands for 'Emotional Part.' Deals with traumatic memories.

Alter
Also commonly referred to as parts, especially in clinical spaces. Dissociated states of consciousness found in DID and OSDD1. More often than not can take full control of the body and view themselves as separate individuals rather than different aspects of one person. May or may not have different identifications than the body, e.g. gender, age, or species.

Fragment
Undifferentiated or undeveloped alters that are flat or one-dimensional in thought processes, actions, or purpose. May exist to carry out a specific function or hold a single memory or part of a memory.

Introject
An alter based on an outside source, fictional or factional. Typically has exomemories/pseudomemories.

Non-Human
An alter that is not a human.

Syskids
An alter that's under the age of 5.

Littles
An alter thats between the ages of 5 and 12

Middles
Teenage alters, between the ages of 13 and 17

Bigs
Adult alters, 18+

Age Sliders
Alters who's age changes between a set range (ex: 13-18), Typically due to external factors, exomemories, or stress. Not to be confused with natural aging or age regression.

Host
The alter that fronts the most and takes care of daily life.

Singletsona
The masking persona of a system, the identity that all alters pretend to be when they're pretending to not be a system. Typically the host's identity.

Co-Host
Another alter that fronts almost as frequently, or just as frequently as the host. Helps them manage daily life and social matters.

Gatekeeper
Alter that controls who accesses specific memories, the front, or places of the headspace.

Soother
An alter thats primary focus is taking care of other headmates or littles, usually helps take care of mental health.

Caregiver
An alter thats primary focus is taking care of other headmates and the body.

Protector
An alter thats primary focus is protecting the body from external stressors, physically or not.

Avenger
A subset of protector that is primarily driven by protecting the system from past, present, and future abusers.

Persecutor
An alter that harms the body, system, or systems relationships. They're typically misguided protectors trying to protect the system, but have skewed views of how to protect themself due to abuse.

Internal Self Helper
AKA ISH, Manager or Observer. Most aware of all alters and the system, manages new alters and memories, works alongside the gatekeeper.

Memory Holder
An alter that hold either positive memories or traumatic memories so the others don't have to deal with them; acts as an amnesia barrier between the brain and trauma.

Symptom Holder
An alter that has a high concentration of a specific disorders traits, so the others may function easier.

Amnesian
An alter thats completely seperate from trauma. Split to purposefully forget trauma. Is often a little and/or the host.

Controversial Terms

Core
The "original alter"; goes against the theory of structural dissociation, which is the basis of DID forming.

Perpetrator
AKA: Trechtor, Malicitor. An abusive alter; Often used to vilify persecutors or shift blame and responsibility off of the system. Perpetuates the stereotype that systems are dangerous/abusive.

System Hopping
An alter hopping from one headspace to another, metaphysically. Thought to be done through astral projection or something similar. Impossible due to how systems work on a physical level.