A legal licence is just authority to do or use something, when if you didn't have the licence it would be wrong or illegal or infringing someone's rights to do or use that thing. Think of it as a right to use someone's property, granted by the owner. The licence sets out the conditions of use almost like a contract. An ordinary licence can be revoked but, just to confuse things, we may or may not be able to revoke a ‘contractual licence’. So we can license the use of software or copyrighted content (e.g. a play) or patented technology or a trademark or a design. Licences are not just applicable to intellectual property, though. We can license someone to occupy a flat or house or land, for example. A licence granted by the government, or its delegated regulatory authority, can also give permission to own (e.g. a dog) or sell (e.g. alcohol) something.