Is it farther or further?
late 14c., "a way of doing something, method; practice, custom, usage;" also "an applied science;" from Old French practique "practice, usage" (13c.) and directly from Medieval Latin practica "practice, practical knowledge," ultimately from Greek praktike "practical" (as opposed to "theoretical;" see practical). From early 15c. as "practical aspect or application of something; practice as opposed to theory;" also, "knowledge of the practical aspect of something, practical experience."