practise [LME] The rule that in British English (but not US) the verb practise is spelled with an ‘s’ and the noun practice with a ‘c’ has only been standardized since the 18th century. The ‘s’ of the verb comes from Old French practiser, the noun keeping the original ‘c’, on the pattern of pairs such as advise, advice. The source is Latin practica ‘practice’, from Greek praktikē ‘concerned with action’.