What did reserves in roman army do

The Roman term “reserve” in the army did not have the same meaning as today’s term. Today, at least in the United States, the term reserve is used to connote our “part time soldiers” or “weekend warriors” who at one time, would train for a certain period of time after they had completed their military service in order to be ready if they were called up. This practice has been discontinued. The Roman army did have a “reserve” which was the third line in a cohort’s battle formation. It was made up mostly of veterans and was used to reinforce the front two lines and to step up when the front lines were depleted or needed a rest.