The nine types are: 1-Reformer/Perfectionist (principled, self-controlled), 2-Helper (caring, generous), 3-Achiever (ambitious, image-conscious), 4-Individualist (creative, introspective), 5-Investigator (analytical, private), 6-Loyalist (committed, security-seeking), 7-Enthusiast (spontaneous, busy), 8-Challenger (powerful, assertive), and 9-Peacemaker (easygoing, accommodating). Each type is defined by a basic fear and a basic desire, for example, Type 6 fears being without support and desires security, while Type 4 fears having no identity and desires to be uniquely themselves.

The nine types split into three 'centers of intelligence,' each organized around a core emotion. The Gut/Body center (8, 9, 1) is driven by anger and the issue of control. The Heart/Feeling center (2, 3, 4) is driven by shame and the issue of image and identity. The Head/Thinking center (5, 6, 7) is driven by fear and the issue of security. Knowing your center explains the emotional 'weather' underneath your type, why a 5 and a 7 can look very different yet both be wrestling with fear.

Your wing is one of the two types adjacent to your core type that adds nuance to your personality. For example, a Type 4 can have a 3-wing (4w3, often called 'The Aristocrat') or a 5-wing (4w5, 'The Bohemian'), each creating a distinct subtype. Most people lean noticeably toward one wing, though a few sit balanced between both. Your wing doesn't change your core type, it shades how that type expresses itself.

Each type is connected by lines to two other types on the Enneagram: one it moves toward under stress (disintegration) and one it moves toward in growth (integration). For example, a healthy Type 1 takes on the spontaneity of a 7, while a stressed Type 1 takes on the moodiness of a 4. These arrows are what make the Enneagram dynamic rather than a fixed box, they describe how you actually shift across good days and bad.