Noun
The previous life and experiences of a person, especially a character in a dramatic work, but also a real-life person.
Coordinate term: exposition
A fictitious account of a person's history designed to conceal their actual history and motives.
Synonym: cover story
A prequel.
Source: en.wiktionary.orgA decade earlier, Inspector Vijay Khanna in Prakash Mehra’s 1974 Zanjeer, one of mainstream Hindi cinema’s first cops with a backstory, uses his temper and fists as the only way to keep criminals in check. Source: Internet
Alien ecologies and mysterious intelligences were incorporated into Alpha Centauri as external "natural forces" intended to serve as flywheels for the backstory and a catalyst for many player intelligences. Source: Internet
Although the upcoming movie isn't an origin story, most viewers are expecting it to shine a light on Natasha Romanoff's MCU backstory. Source: Internet
All this backstory would come as a surprise to a reader of the ’ version of events. Source: Internet
Bo Peep's explanation seems to fill in the gaps in her backstory and let us know what she was up to while the rest of the gang was dealing with Sunnyside Daycare and living with Bonnie. Source: Internet
Character development In a 2001 interview, Rowling said Voldemort was invented as a nemesis for Harry Potter (the protagonist of the novels), and she intentionally did not flesh out Voldemort's backstory at first. Source: Internet