Any pattern or system (including any ideology, philosophy, religion, science, or tradition, as well as coexistent combinations thereof) by which people know or believe (or believe that they know) the things that they know or believe (including any ontologic or cosmologic facts, theories, hypotheses, catechistic items of faith, or other items of faith).

Epistemic modal logic, a subfield of modal logic that is concerned with reasoning about knowledge. / Dynamic epistemic logic, a logical framework dealing with knowledge and information change.

(philosophy) A specific form of rationality focusing on coming to accurate beliefs about the world based on available evidence.

(epistemology, countable) A circle of (foundational) epistemic arguments where the reliability of a device used within this circle is also proven within the circle.