I've always defined a "raghorn" as a smallish brow tined bull. Generally with 4 points or less on one side, but if a 5x5 bull had really small antlers (narrow spread, thin tines) then I would probably call it a raghorn too.
I would say they would typically represent a 2 1/2 year old animal. At 3 1/2 most should be solid 5x5's.