The Enneagram is a personality typing system that consists of nine different types. Everyone is considered to be one single type, although one can have traits belonging to other ones. While it’s uncertain whether this type is genetically determined, many believe it is already in place at birth.
The nine types (or “enneatypes”, “ennea” means “nine”) are universally identified by the numbers 1 to 9. These numbers have a standard way of being placed around the Enneagram symbol. Enneagram authors have attached their own individual names to these numbers. On this site the type names by authors Riso and Hudson are used.
People of a particular type have several characteristics in common, but they can be quite different nevertheless. It depends among other things on their level of mental health. Unhealthy (neurotic) people from a particular type can look quite different from healthy ones. Riso and Hudson distinguish 9 levels of mental health (see their book Personality Types) and have type descriptions for each level of each enneagram type.