It's taken from "Free as in [Free] Beer vs Free as in [Free] Speech" Gratis vs Libre - the former is zero cost (i.e., you're not paying for the free beer), the

It's taken from "Free as in [Free] Beer vs Free as in [Free] Speech" Gratis vs Libre - the former is zero cost (i.e., you're not paying for the free beer), the latter is some cost (i.e., there is a price for free speech - we need to defend the right, accept we won't like everything that is said, etc.)