An onomatopœia, om nom nom is a sound Cookie Monster makes when he eats. The term became a meme on the Internet, often being used with lolcat images. The term, without the lolcat association, was first posted on UrbanDictionary.com in December 2004 as "om nom".
As defined by the Linguistic Society of America, nom is an "Onomatopoetic form connoting eating, esp. pleasurably. Can be used as an interjection or noun to refer to delicious food."
Many viral videos of animals eating feature the term in their titles; among the most viewed are a hamster eating (with 11.4 million views on YouTube), and a "kitteh" (with 2.7 million views). Even Disney Living marketing has used the term.
As of 2011, Sesame Workshop does not seem to have standardized usage of this term, to capitalize on its popularity; paint line Sesame Street Colours includes the variety "Num Num Num".
2nd place in Word of the Year
At the 2011 conference of the Linguistic Society of America (LSA), the final round of the annual 2010 Word of the Year (as voted on by the American Dialect Society) debate was between "app" and "nom". In preliminary rounds, "nom" was up against several other words in the category "Most Useful".