RDF stands for 'Resource Description Framework', which is a special kind of database. It's a way of storing information on the web that can be used by computers and machines (not just humans) to understand what the data means. It helps to make sure that different organizations can share and use data in the same way, using the same terms and definitions. For example, if two companies wanted to exchange customer information, they could use RDF to make sure their computers can agree on what each customer's details mean.