Empiricism is a cluster of different claims about knowledge, all emphasizing the role of experience.
Materials empiricism Materials empiricism is the thesis that all the materials for knowledge come from experience. The content of all of our thoughts is ultimately traceable back to some experience or other.
Justification empiricism Justification empiricism is the thesis that any justification for a claim has to appeal to experience.
Note that the two can come apart. So I might be a materials empiricist and yet deny justification empiricism, because I think that some claims (e.g., analytic claims) can be justified merely by the concepts involved.
Largely opposed to empiricism is a set of claims we will call rationalism:
Materials rationalism Materials rationalism is the thesis that at least some of the materials for knowledge do not come from experience.
Justification rationalism Justification rationalism is the thesis that at least some justifications do not appeal exclusively to experience.
Independent of the empiricist/rationalist debate is a question about the order of knowledge:
Existentialism Existentialism is the thesis that before one can know the essence of a thing, one must first know that it exists.
Essentialism Essentialism is the thesis that one can (or even must) know the essence of a thing before one can know that it exists.
Another debate in epistemology relates to the role of perception:
Direct realism Direct realism is the thesis that, in perception, we are directly perceiving real, ordinary objects.
Indirect realism The opposing thesis, indirect realism, claims that in perception we directly perceive only our own ideas or sensations. It is only because these ideas represent (or are ‘about’) objects in the world that we can be said to perceive those objects.