Was it a term for "the people" or did he mean something like the National Guard?
The word "militia" in the late 1700's meant every male between roughly the ages of 17 and 45. It was definitively NOT anything like the National Guard. First of all, such a body was referred to as a "select militia," so as to distinguish it from the regular militia. Second, the National Guard is a creature of the 20th Century - it is nominally under the command of the states, but is subject to Federalization by the President at the stroke of a pen. It might as well be the regular armed forces.
You should read The Federalist Papers and, in particular, #46 by Madison. It lets you know who the militia is, and its purpose.
What I'm trying to clarify is the concept that anti gun rights people use to argue that "militia" means some type of "group" of people. They then conclude that the second ammendment does not pertain to an "individual's" right to bear arms.