The_Bad_one, That's not my definition, that's what's used in the Militia Act of 1903, which describes two groups.  The organized militia consists of State militia forces, notably, the National Guard and Naval Militia.  The unorganized militia consists of every able-bodied man of at least 17 and under 45 years of age who is not a member of the National Guard or Naval Militia.  The Second Amendment grants gun ownership rights to members of a "well regulated militia" -- the organized militia, not the unorganized militia.