Sweat of the brow (any work you do is copyrightable) https://en.wikipedia.org/wiki/Sweat_of_the_brow

vs.

"Original work of authorship" https://en.wikipedia.org/wiki/Copyright_law_of_the_United_St... (in particular the comparison section https://en.wikipedia.org/wiki/Copyright_law_of_the_United_St... )

The court case that set this difference down was Feist Publications, Inc., v. Rural Telephone Service Co. https://en.wikipedia.org/wiki/Feist_Publications,_Inc.,_v._R....