As your troops engage in battles, they progress from being raw recruits to acting as grizzled veterans, this is represented by the
Experience level of a regiment.
Experience is a numerical representation of how much a regiment has learned and can be viewed by hovering your cursor over the
Experience icon while a regiment is selected. When a regiment gains a certain amount of
Experience, they advance to the next level, becoming more effective combatants. Regiments start out as recruits, and there are three additional levels of
Experience that they can earn as they progress through the battle:
Experience Levels
Recruit 0
(no symbol)
Regular 150
Single chevron
Veteran 350
Two chevrons
Elite 600
First sergeant

Source: Axis and Allies RTS Official Manual