FINDABLE: Metadata and data should be easy to find for both humans and computers.
ACCESSIBLE: Once the user finds the required data, s/he needs to know how can they be accessed.
INTEROPERABLE: Data usually need to be integrated with other data. And data need to interoperate with applications or workflows for analysis, storage, and processing.
REUSABLE: Metadata and data should be well-described so they can be replicated and/or combined in different settings.