What is epistemology?

Technically epistemology is the study of knowledge, but at A-level, you need to know that it's the weight behind any philosophical argument and will be incredibly useful to include in any theory you use. For example: is it a priori or a posteriori? Empirical or rational? Synthetic or analytic? If you can kick off any argument with your epistemology then you'll be on stronger footing for arguing for or against it, and you'll have ticked another box for the examiner.