early 15c., practicale "of or pertaining to matters of practice; applied," with -al (1) + earlier practic (adj.) "dealing with practical matters, applied, not merely theoretical" (early 15c.), or practic (n.) "method, practice, use" (late 14c.). In some cases directly from Old French practique (adj.) "fit for action," earlier pratique (13c.) and Medieval Latin practicalis, from Late Latin practicus "practical, active," from Greek praktikos "fit for action, fit for business; business-like, practical; active, effective, vigorous," from praktos "done; to be done," verbal adjective of prassein, prattein "to do, act, effect, accomplish."
Practical joke "trick played on someone for the sake of a laugh at his expense" is from 1771 (earlier handicraft joke, 1741).