What\'s the difference between a praefect and a praetor?

[Jona Lendering]

A praetor is an official office with imperium: the praetor -always a senator- was allowed to command armies, but at some stage became responsible for the administration of right (more...). A praefectus is usually a military commander, without imperium. Praefecti could be used anywhere (more...).

During the Empire, you wouldn't meet praetores in the army, but many praefecti.