In the broader world of politics, “liberal” usually refers to “classical liberalism”: representative democracy, a capitalist market economy with limited government involvement, and an emphasis on individual liberty over communal well-being. This is the ideology the US was founded upon (for white people, at least) and that it still largely embraces. Both major US political parties are liberal parties.

https://en.wikipedia.org/wiki/Classical_liberalism

Within the US, the user of the term is very different. Republicans use the word “liberal” as a pejorative to describe anyone even slightly to their left. You could be a progressive, a social democrat, a communist, an anarchist, or simply a pragmatic individual who wants to fund libraries and public schools, and you would be branded a “lib.”