Age Slider – A system member whose age is not fixed. Instead, their age changes back and forth as opposed to linearly progressing towards older.
Blending / Blurring / Being Meshy – Experience where more than one system member get mashed together and can't distinguish themselves. For some, it is essentially a slight merging. Can be confusing to the blended members; also can be either distressing or relaxing depending on circumstance. Some even enjoy it.
Core / Host – The central member of a plural system or the member that the others depend on for existence. Note, there is not always a core or host and sometimes there is more than one. Sometimes “core” refers to the central or average identity of a median system, which may not necessarily match up to any one of its members.
Cycling / Revolving Door – Switching rapidly. May be done intentionally, or may be unintentional. Often referred to as the “Revolving Door” or “Revolving Door Switching” when it is unintentional, which may happen when the system's body is sick or the system is experiencing stress.
Daemon – Personification of a person's mind, consciousness, or soul. They usually have a name, gender, and a form. Their form is usually that of an animal. Both singlets and members of plural systems can find their daemon. They are usually not considered to be systemmates.
Deflector – deflectors deflect feelings that may be causing difficulties.
DID/MPD and OSDD/DDNOS – These are psychiatric diagnoses for someone who is plural, usually by way of trauma. Many visited a doctor/therapist because of feeling disordered or dyscommunicative, but not all of them are.
Dissociation – Detaching from one’s surroundings, which can be voluntary or involuntary. Has many forms, including derealization, depersonalization, daydreaming, passing control of the body to another system member, going into headspace, blocking traumatic memories, etc. Getting lost in a book, daydreaming, blocking out the hum of an air conditioner, etc. are all common dissociative experiences – dissociation is not exclusive to plurals, nor is it inherently unhealthy.
Gateway System – a specific kind of system where the people who front are residents of an inner-world/other-world.
Inner-world / Other-world / Headspace / Wonderland – A place that members of a system may reside and/or visit. “Inner world” and “headspace” are more common in the larger community. “Other world” is nice because it doesn't have any implication about where it's located.
Integration / Fusion / Merging – Two or more system members combining together to form one member, whether temporarily or permanently (“integration” and “fusion” generally refer to permanent mergings). Merging is also used to indicate a more complete form of blending. Many therapists think that merging all members of a system together will make for a happy and functional singlet. While this does work for some systems or partial integration may be necessary for some systems, it does not work and/or is not desirable for other systems. For the latter, this can be because it doesn't last indefinitely, may hurt healthy functioning, lead to feelings of loss, etc. or just otherwise not be desired (many systems see integrating with their systemmates as akin to killing them).
Losing Time – The experience of losing memory of, or track of, passage of time. May happen to anyone, not just plurals, for reasons as simple as preoccupation. It is not a pathological symptom, and is commonly overdiagnosed as dissociative episodes even in healthy people. However, it still remains one of the key criteria for diagnosis of DID, as many multiples experience time loss as a result of being inside their headspace while someone else is in front.
Median / Mid-continuum – A system with members who are not inherently independent from each other, and are often dependent on a single individual and unable to exist without that central person. Often consists of members who all identify as aspects/facets of one central identity: e.g. “We are all different, but we are all Mary in the end.” Some believe, mistakenly, that it is the only term that applies to systems where system members are co-conscious, to non-traumagenic systems, or to systems not diagnosed with DID/MPD or OSDD/DDNOS.
Mentalese – Communication within a system that does not consist purely of words: the transfer of emotions, impressions, images, and other raw ideas between system members. For some system members, this can be the preferred or only mode of communication throughout their existence.
Naturals / Natural System – A system whose origin is not from trauma (non-traumagenic) or from a singlet creating systemmates (one way to do this is to make a tulpa). Essentially, they were born plural or got walkins later on spontaneously. Note, this does not mean that the system has not experienced trauma - just that it was not the system's origin.
Original / Birth Person – The first person in a system, or the person who is closest to being that person. Not all systems ever had an original, or the original no longer exists. If an original is present, they may or may not be the core/host.
Otherkin – Someone who identifies as not human, in whole or in part. Therians are a subset of otherkin whose non-human identities are animals that live or have lived on Earth.
Plural / Multiple – a state of having more than one person/consciousness in a body.
Polyfragmented - a type of plurality where systems are composed of a large number of fragments which combine to create headmates. Fell out of popular use and the medical literature after the 80s.
Projection – Physically hallucinating the presence of a system member in outerworld. Can range from simply “feeling” the presence of a system member nearby, to physically hearing a system member when they speak, to being able to see and touch a system member like one would with a physical person.
Prompt / Trigger – A certain sensory stimulus; e.g. a certain food, specific music; that pulls a system member closer to the front, with varying degrees of strength – some prompts may only tug at a member’s attention, while others may induce a member to suddenly and completely take control of the front. Sometimes called “trigger”. Terminology is shifting in order to avoid confusion with the PTSD/anxiety definition of triggers.
Psychomatic Shift – A physical trait or shift that the body acquires upon a certain fronter taking control. For example, the body may acquire an allergy while Member A holds the front that it will not have when any other members are at front, or the body’s eyesight will change in such a way that a system will need to change eyeglasses when changing fronters. These shifts can and have been empirically measured in multiple scientific studies of DID.
Reflector – The person in charge of the body at any given time that is reflecting back in what is seen & heard outside of the body. Also referred to as front, front runner.
Servitor – A non-sentient thoughtform (contrast with a tulpa) created with the purpose of automating or assisting with a certain task – these tasks can be both mental and physical, by way of having the servitor control the body. Essentially a highly refined and elaborate autopilot – can be likened to a method in a computer program.
Singlet – someone who is not part of a plural system; a single person in a single body.
Soulbond / Muse / Living Character – A system member originating from a strong connection to and having the identity of a fictional character, from the work of someone either inside or outside the system, or a person in outerworld (living or dead). The former are known as fictives, and the latter are known as factives. Some natural tulpas could be considered soulbonds.
Splitting – The process by which one system member splits into two or more members, each having a distinct identity. The process often involves a change in the personality of all members created from the split, distinct from the original member, and can occur in a plural system member or a singlet. It should be noted that not all splits are a product of trauma, and that a split can be voluntarily invoked.
Subsystem – A system within a system – nested plurality. Can refer to a member of a system who is median, but has non-median systemmates, or systemmates who share a headspace body much as systems share an outerworld body, etc.
Sychronocitor – coordinate the feelings and thoughts in reference to events that have taken place. Especially events that seem they may have happened or perhaps should have happened.
Traumagenic – Originating from trauma. An adjective that can refer to a system as a whole, a subsystem, or some fraction of the members of a plural system. Meant as a replacement for the problematic term trauma-based.
Tulpa – A thoughtform (created systemmate) who is a full person as opposed to a non-sentient fragment/shard such as a servitor. Can be created by a singlet or a member of an existing plural system including another tulpa. There are three varieties. Deliberate tulpas are those who were made deliberately. Accidental tulpas were tulpas made by someone listening too hard inside and the brain generating someone spontaneously in response. Natural tulpas are imaginary friends, daydream characters, dream characters, etc. who come to life (substantial overlap with soulbonds.
Walk-in – A system member who simply shows up in the system out of the blue, possibly from elsewhere. Can be fictive, factive, or neither. May be human or otherkin. Walk-ins may become permanent system members, or may ‘walk back out’ of their own accord and leave the system without a trace.
Widget – a widget becomes part of the scenario due to a specific need that can be met by a specific individual at an age appropriate to the situation. Some also define this as an age slider.
& – This isn’t exactly vocabulary, but it is becoming common. It is a way to form a plural from something that is not usually explicitly plural, like “you”. “How are you&?” implies asking how everyone is doing. Likewise, signing a message “- Fuzzy&” might imply, “Fuzzy and others”.