Defined most simply, it is the state of having more than one person in one body. It is the opposite of being a singlet. This can take a variety of forms, from having people who may see themselves as parts of one person and individuals at the same time, and those who see themselves as being fully fledged individuals, as distinct as anyone else in the world. The plural community is vast and contains many smaller communities which may or may not get along, and know about the existence of other communities like them.
This refers to cooperative plurality that allows the people in the system to function and thrive in society. This can be the case no matter what the origin of the system was, and whether the DID/MPD or OSDD/DDNOS label is applied or not. This may also be referred to as empowered plurality in some circles.
There are various communities that the plural community encompasses. Some, like the tulpa community, focuses on inducing a sort of plural state, which is often said to improve members's mental and physical health. Other communities, like what may be termed the wider endogenic community, focus more on the experiences that arise sharing a mind and body with others who may or may not have had a choice in the matter. Still others like the DID and OSDD communities seek to understand what is going on, and recover from the effects that trauma and dissociation has on their plurality or identities.