There are many different ways to answer this question, as there are many different types of citizenship. In general, a citizen is someone who is a member of a particular country or nation and is entitled to all the rights and privileges that come with that status. In some cases, citizenship is inherited from one's parents, while in others it is granted after meeting certain criteria, such as passing a citizenship test or completing a period of residency. Some countries also have dual citizenship agreements with other countries, which allows citizens to hold citizenship in both countries.