The public domain is material that is not covered by intellectual property rights.
Material might be in the public domain because it was never capable of being owned. Examples would be the English language or the formulae of Newtonian physics. Alternatively, something might be in the public domain because rights have expired. The works of Shakespeare or the patents over powered flight are examples.
- James Boyle. "The public domain: enclosing the commons of the mind", 2008. p. 38. Referenced 2011-10-11.