Software that is no longer being sold or supported by its publisher. Most abandonware is still considered illegal unless the publisher has re-released the software as
freeware.
U.S. copyright laws state that copyrights owned by corporations are valid for 75 years from the date the software was first published. So the current availability of a product is irrelevant to its copyrighted status. Unlike trademarks, copyrights are not considered abandoned if they are no longer enforced. Copyrights do not enter the public domain just because they are no longer commercially exploited or widely available.