FREEDOM is self-determinance; it is the condition of minimal constraint. Naturally, in a society or community, there has to be some constraints — the burglar cannot have the freedom to steal, the thug cannot have the freedom to mug, and the businessman cannot have the freedom to excessively pollute and pay no taxes. But get the balance between personal freedom, social order and ecological integrity right, and the vast majority of citizens can live happily with moderate personal freedom and minimal constraints.
Our freedom and constraints are formalized into a long agreement between each individual (or legal entity such as a company) and the society of which he she or it is a part. This formal agreement is called the law or legal system and it is constantly evolving and changing as new situations and circumstances arise. (Parts of this legal system, usually those dealing with human rights, are deliberately less changeable and are sometimes called constitutions.) So our freedom is defined and upheld by the legal systems.
A common fallacy regarding freedom is to automatically assume that it is a byproduct of modern democracy. In fact, the "only" freedom that a democracy bestows practically on its members is that they have the right, every few years or so, to vote for one of a set group of representatives (government) who will run the country on their behalf. Whilst modern democracy is an indispensable foundation for free societies, it does not necessarily guarantee freedom. That job falls to the legal system, which is not so readily influenced by our periodic voting. (Which is why freedom campaigns often involve legal challenges.)
Democracy can only be an agent of freedom if it gives the people meaningful voting choices (not just a choice of 2 or 3 parties which have only cosmetic differences), and if it ensures that the people have the unbiased and undistorted information necessary to make a choice that is in their interest (in other words, a mass...