Absorption describes the journey a medicine takes from the place it enters the body to the bloodstream that carries it around. For a tablet or capsule swallowed by mouth, that means dissolving in the stomach and small intestine and crossing the gut wall.
Absorption matters because it helps explain why a swallowed medicine does not act instantly, why food can sometimes change the experience, and why the same active ingredient can feel slightly different in liquid form than in tablet form. Official labeling summarises absorption in a section usually titled Clinical Pharmacology.