backstory

or back sto·ry

[bak-stawr-ee, ‐stohr-ee]

noun, plural back·sto·ries.

a narrative providing a history or background context, especially for a character or situation in a literary work, film, or dramatic series.
prequel.

Origin of backstory

1980–85; back¹ + story¹

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for back story

back story

noun

the events which take place before, and which help to bring about, the events portrayed in a film

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for back story

backstory

c.1990, from background story.