The Astrate – means literally "in the middle of the atmosphere." Land with the highest elevation of any place inhabited by humans, situated literally above Petrogea, at the tops of the mountains and cliffs. Its inhabitants are called Astrateals.

Petrogea – means literally "rock world." Land in the mountains in the northeast of the Ground Earth. Inhabitants are called Petrogeans. Petrogeans and Astrateals hate each other.

The Ground Earth – the main part of the world, including all of the earth but the highlands (Petrogea and the Astrate), Pelagia (the islands), and the newly discovered underworld. Commonly referred to as "The Lowlands" by Astrateals and Petrogeans.

sabaent – an Astrateal word meaning literally "true human." Once an Astrateal reaches maturity, they must either prove to be a sabaent or die.

fealtain – Astrateal term for a man bound to a woman as her protector. Fierce and skilled warriors. A woman may have many fealtains, but a man may only be bound to one woman. Most often become emotionally attached to their women.

hyrin – the rough fibers of the plan hyra, one of the few plants that flourishes in the Astrate. Commonly woven into clothing.

Sagreu – Astrateal word meaning literally "test." Has two definitions:
1) a ritual in which all Astrateals must participate in order to become a sabaent, which involves leaping over a cliff believed to be sacred. It is believed that if a person is worthy to live, the god Sa'Kero will carry them safely across to the other side on his back.
2) the cliffs over which the person leaps

Sa'Kero – the main god of the Astrateals, who takes form of a giant eagle. Name means "true freedom."

The Overlord – the god of the Petrogeans