c.1400, "to do, act;" early 15c., "to follow or employ; to carry on a profession," especially medicine, from Old French pratiser, practiser "to practice," alteration of practiquer, from Medieval Latin practicare "to do, perform, practice," from Late Latin practicus "practical," from Greek praktikos "practical" (see practical).
From early 15c. as "to perform repeatedly to acquire skill, to learn by repeated performance;" mid-15c. as "to perform, to work at, exercise." Related: Practiced; practicing.