Clairvoyance

Clairvoyance, also known as voyance, is the ability to access the æther, or the spirit realm. Those who have clairvoyance are called clairvoyant, or voyants for short.

Description
While many clairvoyants view their abilities as a gift, a common saying in the syndicate is "the æther takes as often as it gives." All the voyants pay a price for their connection to the spirit world. For example, Paige gets nosebleeds and bouts of fatigue. Nick gets migraines. Eliza loses control over her body when she is possessed by a spirit.

Types of Clairvoyance
The seven orders of clairvoyance, according to On the Merits of Unnaturalness by Jaxon Hall: According to On the Merits of Unnaturalness, the first Order, Soothsayer, is the most common, while the last Order, Jumper, is the rarest. This does seem to be generally true.

Etymology
The word clairvoyance comes from the French words clair, meaning "clear" and voyance, meaning "vision." Thus, the word clairvoyance means "clear vision."