Increasingly, and especially with respect to comics, "retcon" also refers to stories which retroactively change the history of a character or fictional world.
In the 1980s, for example, excellent revision of Catwoman post-Crisis on Infinite Earths made her a former prostitute, even though this had never before been mentioned. That retcon has since been retconned out of DC continuity; the character retroactively never was a whore. Her sister, a nun, did not die, but retroactively never existed.
Later still, portions of this history, including Catwoman's saintly sister, were re-established as being part of the DC Universe.
Perhaps the most infamous retcon from American television involved the 1970s series, Happy Days. Chuck Cunningham, older brother of central character Richie, retroactively ceased to exist after two seasons; he was never seen nor mentioned again, and the Cunningham parents spoke only of their two children, Richie and Joanie.