A Princeps was a command level position held by an Augment in the Earthfleet of the Children of Khan.

Julian Bashir held the position of Princeps of the starship Defiance in an alternate timeline where the Augments succeeded in conquering the Earth during the Eugenics Wars. Ethan Locken also held this rank in this alternate reality. A Princeps usually had an Optio as his second in command. (DS9 novel: Seeds of Dissent)