Definition from Wiktionary, the free dictionary
backstory (plural backstories)
- The previous life and experiences of a character in a dramatic work.
2004 January 16, Kelly Kleiman, “Her Side of the Story”, Chicago Reader:
- These backstories cast the characters' behavior in a new light: of course Gertrude would promptly marry the man who saved her from abuse; of course Ophelia would be desperate and indiscreet in seeking Hamlet's love.
- A fictitious account of a person's history designed to conceal their actual history and motives; a cover story.
- A prequel.
previous life and experiences of a fictional character