The Baader-Meinhof phenomenon is an illusion where, once you learn about the existence of something, you can't stop seeing it around (for example, this keeps happening to me with people saying based off of instead of based on, after I found out that was a common mistake). Now, looking at the name of the phenomenon, one would naturally assume that it's after the pair of psychologists or linguists who first documented it, but it actually traces to the Baader Meinhof Group, a left-wing West German terrorist organization active in the 1970s-90s. The connection is from a 1994 comment on the message board of the St. Paul Pioneer Press where the person noted that they heard two references to the gang in the last 24 hours and dubbed it a phenomenon. After that, a lot of other people started using the phrase, and it became an actual psychological term.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.