This article covers a topic that has not been fully explored on the show and thus contains some information taken from the books, in addition to information from the TV series.
The Clave is the collective name for the political body made up of all active Shadowhunters. The Clave interprets the law and makes decisions on important matters that affect the Nephilim, which also sometimes affect the Downworlders.
All Shadowhunters who recognize the authority of Idris make up the Clave. While Clave members hold a sway in decisions made regarding important matters relevant to their race, final decisions are made by the Council. The Consul and the Inquisitor are also important figures in the organization.
The term "Clave" comes from the Latin clavis, meaning "key," and its use in such terms as "Enclave" and "Conclave" refers abstractly to the idea of an assembly "under lock and key"—that is, meeting in secret. The Clave is, so to speak, the great secret of the Nephilim; with the key of the Mortal Cup, one earns entrance to its chambers.