Retcon is a verb that means ‘to revise an aspect of a fictional work.’
A recent addition to the English language, retcon emerged in the 1980s as an abbreviation for the words ‘retroactive community.’ Mostly used as a verb, it may also be used as a noun to refer to the act of making a revision to a fictional work. Here’s an example of the word used both a noun and a verb:
I noticed a retcon in the first few minutes of that movie when they tried to bring back a character who had previously died in the last installment. But if anything needed changing, it was the horrible acting. Too bad they couldn’t retcon that.