Practise

wiktionary

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From Middle English practizen, a variant of practisen, from Middle French pratiser, practiser, from Medieval Latin practizo, from Late Latin practico(“to do, perform, execute, propose, practise, exercise, be conversant with, contrive, conspire, etc.”), from prāctica(“practical affairs", "business”), from Ancient Greek πρᾱκτική(prāktikḗ), from πρᾱκτικός(prāktikós, “practical”), from πρᾱ́σσειν(prā́ssein, “to do”), ultimately from Proto-Indo-European *per(h₂)-(“to go over, cross”).

etymonline

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practise

the usual spelling outside American English of practice as a verb. It also is the form of the verb in the U.S.-produced "Century Dictionary" (1889). Related: Practised; practising.