the bigger one is commonly called a shooter --used for shooting at the smaller marbles to knock them out of the circle --if one shot and missed or hit and failed to knock one of the other marbles out and the shooter was left inside the circle it was "stuck" and could be won by another person --ie you could lose yer shooter -- the stuck shooter was treated as if it was any other marble --if one was playing "keepsies" that is -- often shooter marbles were favorites of kids and if you won his favorite shooter --the other kid would trade you a bunch of marbles to get it back --if you liked him you would "trade" his shooter back to em --if you didn't like em -- tough luck fer him. :P