Homer's middle name, "Jay," is a tribute by Simpsons creator Matt Groening to the work of cartoon producer Jay Ward, creator of Bullwinkle J. Moose and Rocket J. Squirrel. At one time Homer knew that his middle initial was "J", but did not know what it stood for. The meaning was revealed to him on a mural that had been painted by his hippy mother when he was a child—the joke being that, in speech, "J" is indistinguishable from "Jay". Abe, Homer and Bart all share this middle initial, though not the name.
https://en.wikipedia.org/wiki/Lisa_Simpson
