backstory

noun

1. The previous experiences and life of a person, specifically (narratology, especially in film, television) a character in a dramatic work.

   “What’s the backstory of our new colleague?”

   “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.”

   “Inexplicably, and at great risk to the integrity of the movie, the filmmakers have burdened him with a psychological back story pulled out of a folder in some studio filing cabinet. Why does [Willy] Wonka spend his days confecting sweets?”

   “Agent Lyla: Enough back story! / Dr. Doofenshmirtz: Actually, that's not, uh … that's not really a back story, it's just expositional flashback. It doesn't, uh, have any childhood trauma, it's doesn't really inform who he is, it's not … it's just flashback. There's a difference. It's subtle, but there's a difference.”

   “Prince Harry may yet turn out to be the crown’s best insurance policy. By marrying Meghan Markle, he is linking royalty with a 21st-century celebrity who has a backstory that many people in Britain can identify with.”

2. A fictitious account of a person's history designed to conceal their actual history and motives.