Liberal, Libertarian...how do you define it?

Like most "labels" it depends on the source:

According to Funk and Wagnall's Dictionary:

lib-er-tar-i-an, n. 1. a person who advocates liberty, esp. with regard to thought or conduct.... advocating liberty or conforming to principles of liberty.

According to American Heritage® Dictionary of the English Language: Fourth Edition. 2000.

NOUN: 1. One who advocates maximizing individual rights and minimizing the role of the state.

The Challenge of Democracy (6th edition), by Kenneth Janda, Jeffrey Berry, and Jerry Goldman:

Liberals favor government action to promote equality, whereas conservatives favor government action to promote order. Libertarians favor freedom and oppose government action to promote either equality or order.

According to Microsoft® Encarta® Online Encyclopedia 2000 © 1997-2000 Microsoft Corporation:

Libertarianism, political philosophy emphasizing the rights of the individual. The doctrine of libertarianism stresses the right to self-ownership and, by extension, the right to private ownership of material resources and property. Advocates oppose any form of taxation and favor a laissez-faire economic system.

According to Libertarian.org:

While libertarians are a diverse group of people with many philosophical starting points, they share a defining belief: that everyone should be free to do as they choose, so long as they don't infringe upon the equal freedom of others.

According to David Boaz, Libertarianism: A Primer, Free Press, 1997:

Libertarianism is the view that each person has the right to live his life in any way he chooses so long as he respects the equal rights of others. Libertarians defend each person's right to life, liberty, and property-rights that people have naturally, before governments are created. In the libertarian view, all human relationships should be voluntary; the only actions that should be forbidden by law are those that involve the initiation of force against those who have not themselves used force-actions like murder, rape, robbery, kidnapping, and fraud.

According to Charles Murray, What It Means to Be a Libertarian, Broadway Books, 1997:

The American Founders created a society based on the belief that human happiness is intimately connected with personal freedom and responsibility. The twin pillars of the system they created were limits on the power of the central government and protection of individual rights. . . .

A few people, of whom I am one, think that the Founders' insights are as true today as they were two centuries ago. We believe that human happiness requires freedom and that freedom requires limited government.

The correct word for my view of the world is liberal. "Liberal" is the simplest anglicization of the Latin liber, and freedom is what classical liberalism is all about. The writers of the nineteenth century who expounded on this view were called liberals. In Continental Europe they still are. . . . But words mean what people think they mean, and in the United States the unmodified term liberal now refers to the politics of an expansive government and the welfare state. The contemporary alternative is libertarian. . . .

Libertarianism is a vision of how people should be able to live their lives-as individuals, striving to realize the best they have within them; together, cooperating for the common good without compulsion. It is a vision of how people may endow their lives with meaning-living according to their deepest beliefs and taking responsibility for the consequences of their actions.