This video introduces what reusability means in the context of FAIR (Findable, Accessible, Interoperable, Reusable) research data management. Reusable research data emphases that a user, either a human or a machine, is able to determine if the data can be used for other purposes than it was originally collected or created for. The data needs to be richly described with accurate and relevant information including a usage licence and provenance information about where the data came from. Additionally, the data should use community-endorsed standards.