The story
Coined by Bob Grumman, who invented the genre, and first attested in 1988; formed as a blend of either mathema(tics) or mathema(tical) with (hai)ku.
Etymology from Wiktionary, CC BY-SA 4.0.
mathemaku
Today it means: A genre of pseudohaiku which combines a very short poetic structure with elegant mathematical expression; also, an example of this genre. Full definition →