Practise and practice are two different words and word class. They are not two different spellings. Practise is a ‘verb’ which means it is an action, just like an athlete will ‘practise’ everyday to succeed in their sport. Practice on the other hand, is a ‘noun’ which identifies, for example a lawyer and their work, their ‘practice’ or name for their work, is law. It can also be the name given to the space where they undertake their profession, for example a ‘law practice’.