Repeating an activity or skill over and over to improve at it; the British English spelling of 'practicing'.
Practice comes from Old French 'practiser' meaning to practice or train, which came from Medieval Latin 'practicus' meaning practical or skilled. The '-ing' form shows ongoing action.
The British spelling 'practising' (with an 's') versus American 'practicing' (with a 'c') is a perfect example of how English split into different standards after 1776—it's just spelling convention, not a difference in meaning!
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