What is the difference between liberalism and libertarianism?

My understanding of the difference:

Libertarianism: Freedom of thought and action and the virtue of self interest, even if this affects other people adversely?

Liberalism (Classical not Modern): As many people as possible have as much personal freedom/autonomy as is feasible, without affecting other people adversely?

(Modern liberalism in America is sometimes thought of as a 'liberal' use of government intervention, as against a more 'conservative' use of government intervention?)