It's fuzzy and imprecise, as many legal concepts are. Small/unoriginal enough snippets may not even be copyrightable: https://en.wikipedia.org/wiki/Threshold_o

It's fuzzy and imprecise, as many legal concepts are. Small/unoriginal enough snippets may not even be copyrightable: https://en.wikipedia.org/wiki/Threshold_of_originality https://en.wikipedia.org/wiki/Threshold_of_originality Then even if it is copyrightable, under some circumstances your use of it may be considered fair use anyway: https://en.wikipedia.org/wiki/Fair_use#U.S._fair_use_factors https://en.wikipedia.org/wiki/Fair_use#U.S._fair_use_factors Or potentially de minimis: https://blogs.library.unt.edu/copyright/2017/09/05/the-de-minimis-defense-in-copyright-law-de-mini-what/ https://blogs.library.unt.edu/copyright/2017/09/05/the-de-mi... But when in doubt, ask for permission or ask a lawyer.