Regardless of its role in the sentence, the correct spelling is always practice with a C. In British and other non-American versions of English, spelling may vary depending on the function of the word. For example, if you are referring to what a doctor does, you would say that they practise medicine. You spell the verb form, practise, with an S.

As I just mentioned, “practise” with an S is the verb form in British English, and “practice” with a C is the verb form in American English. Therefore, if you’re writing for a British audience, you should use “practising,” but if you’re writing for Americans, you should use “practicing” when talking about the verb.

The spelling difference for the verb practise or practice carries over to the present participle forms (ending in the suffix “-ing”). In British English, “practising” is standard. In American English, “practicing” is correct.

The same regional distinction applies to the “-ing” forms of the verb. Both forms can also be used as adjectives. In UK English, “practising” (with an “s”) is standard. In US English, “practicing” (with a “c”) is correct.

Practicing and practising are both English terms. Usage Practicing is predominantly used in 🇺🇸 American (US) English (en-US) while practising is predominantly used in 🇬🇧 British English (used in UK/AU/NZ) (en-GB).