practiceyoudaoicibaDictYouDict[practice 词源字典]
practice: [15] The ultimate source of practice is Greek prássein ‘do, practise’. From its base *prak- were derived the noun praxis ‘doing, action’ (source of English praxis [16]) and the adjective praktós ‘to be done’. On this was based praktikós ‘concerned with action, practical’. This passed into English via late Latin practicus as practice [14], which was later superseded by practical [17].

From practicus was derived the medieval Latin verb practicāre, later practizāre. This passed into English via Old French practiser as practise [15]. The derived noun practise was altered to practice in the 16th century, on the analogy of pairs like advice/advise.
=> practical, practise, pragmatic, praxis[practice etymology, practice origin, 英语词源]
practice (v.)youdaoicibaDictYouDict
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.
practice (n.)youdaoicibaDictYouDict
early 15c., practise, "practical application," originally especially of medicine but also alchemy, education, etc.; from Old French pratiser, from Medieval Latin practicare (see practice (v.)). From early 15c. often assimilated in spelling to nouns in -ice. Also as practic, which survived in parallel into 19c.