Medial means towards the midline, and lateral means away from the midline. For example, the heart is medial and the radius bone is lateral
No they are generally not interchangeable, as far as I’m aware. Medial and lateral are anatomical terms, as Kayli has explained above. The terms “central” and “peripheral” are used more in physiology. E.g., CNS & PNS, or central chemoreceptors and peripheral. It does not necessarily imply anatomical location.