According to Merriam-Webster Dictionary, Ontology is defined:

Essentially it's asking, "What is the nature of the disease, the world, or X?" Analyzing things to confirm or deny it's what we know or believe it to be.

Epistemology on the other had is defined as,

This is concerning the question "How do we understand a disease, the world, or Y?" Essentially, how do we know, what we know?

These words are important to understand when looking at and analyzing research.