folk-lore

Noun

folklore (countable and uncountable, plural folklores)

1. The tales, legends, superstitions, and traditions of a particular ethnic population.
   • [T]here is no true American music but the wild sweet melodies of the Negro slave; the American fairy tales and folk-lore are Indian and African; and, all in all, we black men seem the sole oasis of simple faith and reverence in a dusty desert of dollars and smartness.1903 April 18, W[illiam] E[dward] Burghardt Du Bois, “Of Our Spiritual Strivings”, in The Souls of Black Folk: Essays and Sketches, Chicago, Ill.: A[lexander] C[aldwell] McClurg & Co., →OCLC, pages...
2. (broadly) The tales, superstitions etc. of any particular group or community.
   • A selection of longer items of hacker folklore and humor is included in Appendix A, Hacker Folklore.1996, Eric S. Raymond, The New Hacker's Dictionary, 3rd edition, MIT Press, →ISBN, page 3
3. (slang) The collective of proofs or techniques which are widely known among mathematicians, but have never been formally published.