mythos

Short definition from Wiktionary

Noun

1. 1
   Anything transmitted by word of mouth, such as a fable, legend, narrative, story, or tale (especially a poetic tale).
2. 2
   A story or set of stories relevant to or having a significant truth or meaning for a particular culture, religion, society, or other group; a myth, a mythology.
3. 3
   A set of assumptions or beliefs about something.
4. 4
   A recurring theme; a motif.