Where the Wild Things Are, she inquired, "What's a rumpus?" I told her I wasn't even sure that it was a real word, but assured her I would look it up.
According to my Webster's Ninth New Collegiate Dictionary, the word means, "a noisy commotion." Its origin is unknown, but it first appeared in print in 1764.
R.I.P. Marice Sendak, who died May 8, 2012.