You’ll find that the UK spell checker on your computer allows both practice and practise. Does that mean you can choose which one you like? If only life – and in particular English–were that simple!
No, when practice is a noun, it is spelt with c in British English:
What does this mean in practice?
We need to adopt best practices.
Practice makes perfect.
However, when it is a verb, it is spelt with s:
You must practise more often.
He practises medicine in London.
Of course, that means you need to know how to tell whether it’s a noun or a verb! But that’s not too hard. As a rule of thumb, a verb can have words like I, you or he before it, whereas a noun can have words like the, his or some in that position.
Thanks to Noah Webster,the 18th/19th-century American teacher and dictionary-maker, the spelling in US English is more straightforward. Both the noun and the verb are spelt with c:
Noun: It takes a lot of practice to get it right.
Verb: The team is going to practice this afternoon.
Verb: I haven’t practiced for years.
©2013 Baxter Publishing, Hilversum, The Netherlands