I was curious about M-W's claim to have dated this word to 1948, so I got a second opinion from the OED. The OED says the same thing, it turns out, and goes into further detail:
1948 in Partridge Dict. Forces' Slang. 1962 W. GRANVILLE Dict. Sailors' Slang 53/2 Ginormous, acronymous adjective descriptive of something really impressive: a brush with the enemy; a raid upon the enemy's shipping or coastline, or merely a particularly ‘heavy’ party in the mess.
Oooh, a heavy party in the mess -- sounds like a good time!
I invented the word "ginormous" in 1998 while working at Netscape. It was my combination of "giant" and "enormous". I had tested "egantic" (enormous + gigantic) -- but that had no where near the ring to it of "ginormous".
I really prefer "bignormous" over "ginormous." The beauty of bignormous is that of a yellow schoolbus converted into a methlab and then thrown up on a flatbed truck and filled with schoolkids again. The perfect mix of perversion, human will, and organicity. That, by the way, was a bignormous sentence, not a ginormous one.
"Just two years after a majority of visitors to Merriam-Webster OnLine declared it to be their "Favorite Word (Not in the Dictionary)," the adjective "ginormous" (now officially defined as "extremely large: humongous"), has won a legitimate place in the 2007 copyright update of Merriam-Webster's Collegiate® Dictionary, Eleventh Edition." (http://www.m-w.com/info/newwords07.htm)
Two years? Lame. Especially given that M-W itself dates the word to 1948.
"Juan de Bedout, manager of the electric power and propulsion systems lab at G.E., said this was more important now because wind machines had grown from a few hundred kilowatts to 1.5 gigawatts, and his company was exploring machines four times bigger than that. “That’s ginormous,�? he said." - New York Times, 12/28/06, "It’s Free, Plentiful and Fickle"