Retroactive continuity, or Retcon for short, is a literary device in which established facts in a fictional work are adjusted, ignored, or contradicted by a subsequently published work which breaks continuity with the former.
For Terminator fictions, some of background story or setting are retconned, for examples:
- In The Terminator: Tempest, the story is set in 1990, which is stated in the last page of the first issue. However, in the last installment The Terminator: Endgame, the date setting is changed to 1984.
- John Connor was born in 1985 and he was a 10-year-old when he is targeted by the T-1000 as shown in the film Terminator 2: Judgment Day, however, in Terminator 3: Rise of the Machines, John says he was 13-year-old during the incident in T2. Additionally, Sarah Connor's birth is moved from 1965 to 1959.
- Cyberdyne Systems ceases to exist and is now "ancient history"[1][2] and is replaced with Cyber Research Systems in Terminator 3: Rise of the Machines, however, the company was brought back in Terminator Salvation, while Cyber Research Systems is removed from the fiction.