The Venn Diagram, so ubiquitous in statistics as well as popular science, was named after a person, John Venn, who in 1881 wrote a book about the logical sets. Originally it was named Venn’s Diagram, but the possessive became too cumbersome so it was eventually dropped altogether. It’s hard finding etymologies for surnames, but Venn may be an alteration of a medieval English name, Fenn (this is a good connection to make, especially considering that John Venn was English), which would come from Anglo-Saxon, where it took the form of something like foenn, or a “marsh”. This word has philological relatives in German and definitely traces to Proto-Germanic fanja, from Proto-Indo-European pen, both of which meant “swamp”. Surprisingly, usage of the now-word Venn has only overtaken usage of the name Fenn in the 1980s.
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.