Unfortunately for gun control advocates, the meaning is more obvious than a lot of people want to admit, given the historic context and the nature of the world in which our Founders lived. For example, a militia was made up of ordinary citizen volunteers. They provided their own arms for the most part. Many owned their own rifles, used for hunting and for protecting their livestock from predators. A few (mostly more wealthy individuals) also owned pistols. When the American Revolution required volunteers from the lower classes (indentured servants etc.), arms were provided, but many people brought their own.
Part of the historic context would also have to include that in England and Europe, during the century prior to our Revolution, only aristocrats were allowed to bear arms (swords and pistols). It was a crime punishable by hanging for the lower classes to own them.
We also need to keep in mind that our Founders did not trust government. The Bill of Rights was put in place because of concern that unless some of the basic rights were enumerated, a central government would be tempted (as the prior aristocracies had been tempted) to make rules for some that didn't apply to all.
A militia then, belonged not to the central government, but to the people. In our day, of course, we see how deeply controlled the National Guard is by the Central Government. Just as the Constitution was a work of art designed to divide power among the three aspects of government (the three Branches) in order to set limits on each single Branch, so the Bill of Rights was designed to set general limits on the Central Government, and put the peoples' rights as primary.
See in this regard the ninth and tenth amendments of the Bill of Rights: Ninth Amendment – Protection of rights not specifically enumerated in the Bill of Rights: "The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people." Tenth Amendment – Powers of states and people. "The powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the states respectively, or to the people."
We don't understand the Bill of Rights unless we appreciate that it was created precisely to set as superior the Rights of the People over the limited power granted to the Government by the People through the Constitution. The meaning of the Second Amendment then can't be read alone, but has to be understood as part of a whole.
The existence of a gun culture in America, and of the influence of the history of the West on that gun culture, are social phenomena that while some can find reason to wish otherwise, most Americans like the idea that they have rights which they can defend (a man's home is his castle). That the State (the Central Government or State Governments) wants to effect American culture (crime etc.) by gun control is understandable. However, it is not a decently thought out social policy. If the goal is to reduce violent crime, then the regulation of guns is a very poor choice of a way to proceed. We'd get farther in reducing violent crime by decriminalizing many drug offenses and prostitution, and eradicating poverty (and improving inner city life in terms of schools and medical care). We'd get further by stopping the insane increase of the income of the upper classes at the expense of the lower classes. We'd get further by having sane rules of property ownership that didn't concentrate access to real properly and the ability to grow food into a single class.
The knee-jerk liberal thinking that wants to control guns, already knows that such causes in the Muslim world (power in outsiders rather than in the local communities) creates much of the violence directed against the West. The same is true in America. Gun control is just more of the same - power applied by a central authority on a minority based on its fear driven need to rule. It won't work. Its never worked historically, and it won't work tomorrow.

