212.8b.

Tribal subtypes are always single words and are listed after a long dash: In "Tribal Enchantment — Rebel Aura," "Rebel" is a subtype of tribal. The set of tribal subtypes is the same as the set of creature subtypes; these subtypes are called creature types. Tribals may have multiple subtypes. (You can find the complete list of tribal subtypes under "Creature Types" in the glossary at the end of this document.)