The Open Database License (ODbL) is a license agreement intended to
allow users to freely share, modify, and use this Database while
maintaining this same freedom for others. Many databases are covered by
copyright, and therefore this document licenses these rights. Some
jurisdictions, mainly in the European Union, have specific rights that
cover databases, and so the ODbL addresses these rights, too. Finally,
the ODbL is also an agreement in contract for users of this Database to
act in certain ways in return for accessing this Database.
From the Turtle Research and Monitoring Database System (TREDS)