Folklore is the expressive culture of a particular group, encompassing a wide range of traditions from oral forms like myths and jokes to material culture such as building styles, and customary lore including rituals and celebrations. The term "folklore" was coined in 1846 by the Englishman William Thoms to replace "popular antiquities," describing knowledge and traditions passed along informally. Initially referring to rural, often illiterate peasants, the concept of "folk" has since expanded to include any social group—from a nation to surfers or computer programmers—that shares a common identity through distinctive traditions.

These folklore artifacts are transmitted informally, typically anonymously, and always in multiple variants, fostering a shared community identity rather than being individually copyrighted like high culture. Professional folklorists study these traditions to understand their evolving significance for the group, as their continued relevance is what ensures their transmission across generations and regions. For instance, the meaning of a celebration like Halloween has transformed significantly over time while remaining culturally important.