The word "ontology" is usually synonymous with the word "metaphysics" "the branch of philosophy that attempts to construct a general, speculative worldview; a complete, systematic account of all reality and experience, usually involving an epistemology, an ontology, an ethics, and an aesthetics." This difference in usage is not a big deal. Philosophers don't worry about it they understand what you're getting at, whether you call it "metaphysics" or "ontology." The following are all metaphysical (or ontological) questions: What is reality? What do real things have that unreal things lack? Are some kinds of things (e.g., material things) more real than others (e.g., concepts)? Does a tree falling in the forest if no one is around make a real sound? Is God real? Is the mind a separate substance? If so, how does it relate to matter? What is matter? Does human freedom exist? If so, what is it? Epistemology is the branch of philosophy that investigates the nature, source, and limits of KNOWLEDGE. You can easily figure out what "epistemology" means if you know a little Greek. "Episteme" is the Greek word for "knowledge," and you already know what logos means. The following are all typical epistemological questions:
Is there any knowledge in the world so certain that no reasonable person could doubt it? Is there any secure basis for our future expectations, or is it just a matter of crossing our fingers and hoping for the best? Does science explain -- does it help us to understand anything? or does it merely describe? What, if anything, is the contribution of the senses to knowledge?
Empiricism in epistemology is the view that knowledge does come primarily or solely from the senses.