The dictionary has revised more than 1,900 entries, and some of the new words are shorthand terms in the digital world, including "OMG" - short for "Oh my God" or "Oh my gosh."
Other Internet-inspired expressions given the stamp of approval include LOL, "laugh out loud"; IMHO, "in my humble opinion"; and BFF, "best friends forever."
Dictionary compilers said that although the terms are associated with modern electronic communications, some are surprisingly old. The first confirmed use of "OMG" was in a letter in 1917.
And for those who prefer using fully spelled out words, there is the addition of "muffin top," defined as "a protuberance of flesh above the waistband of a tight pair of trousers."
The dictionary also includes a new entry for "heart" as a verb, a casual equivalent of "to love" that is represented with a symbol, as seen on millions of souvenirs proclaiming "I (heart) New York."
The Associated Press contributed to this report.