The story
First mentioned by Lawrence Lessig in 2004, but it is unclear when observance began.
Etymology from Wiktionary, CC BY-SA 4.0.
Public Domain Day
Today it means: An annual observance on January 1 of when copyrights expire and works enter into the public domain. Copyrights usually expire every year on January 1 based on the individual copyright laws of each country. Full definition →