Core terms:


Host, Tulpaforcer, Tulpamancer, Creator
The original person or human who is creating or has created a tulpa.

Tulpa, Tupper (slang)
An autonomous, apparently sentient entity within the mind of the host, much like another person who has been created by the host and lives in the host's brain.

Form
What someone or something looks like in imagination.

Wonderland
A persistent area created in the host's imagination.

Mindvoice
How one hears vocalised thoughts (one's own and of one's tulpa) in one's mind (i.e. what you sound like talking in your head) - contrast with 'raw thoughts' (how one hears thoughts as ideas). This is not a hallucination; contrast with 'imposition'.


Creation:

Tulpaforce, Tulpaforcing, Force, Forcing
Spending time with a tulpa, developing them. Often split into 'active' and 'passive' forcing.

Active Forcing
When the host dedicates their full attention to their tulpa and the task at hand.

Passive Forcing
When the host only partly pays attention to their tulpa and partly to another activity.

Visualise, Visualisation, Visualize, Visualization
Seeing something in the 'mind's eye', i.e., in the host's imagination. This is not a hallucination; contrast with 'imposition'.

Narrate, Narration
When the host talks to their tulpa consistently, throughout the day. A form of 'passive forcing'.

Deviate, Deviation
When a tulpa changes (usually in form or personality) independent of the host's will.


Communication:

Sentient, Sentience
When a tulpa is able to think and feel, usually taken to be when they can communicate in any way.

Vocal, Vocality
When a tulpa is able to talk to their host via 'mindvoice'.

Emotional Response
When a tulpa sends the host an emotion that feels foreign to the host.


Activity:

Impose, Imposition
The host experiencing the tulpa as a hallucination - usually visual and auditory - or learning to do so.

Possession
A tulpa taking control of the host's body, either part or all  of it. "Partial possession" refers to the former and "full-body possession" the latter.

Switching
The host ignoring the body's senses and experiencing imaginary ones while their tulpa is in control of the body. The state the host experiences while switching is how a tulpa often spends their time in an imaginary world. Contrast to 'full-body possession', where the host still experiences the body's senses.