(CNN) No need to study this month to increase your vocabulary. Merriam-Webster added 840 new words to the dictionary -- and chances are, you probably know many of them.

A bulk of the new entries are already widely used, but a few additions will horrify old-school grammarians.

"Rando," "adorbs" and "fav" are now sanctioned words. Blended words such as "mocktail" or "hangry" (hungry + angry) have made it in their own right. But possibly the most outlandish is "TL;DR," which is shorthand for "too long; didn't read."

"The addition of new words to a dictionary is a step in the continuous process of recording our ever-expanding language," said Merriam-Webster in a statement . "The dictionary's job is to report that usage as it enters the general vocabulary."

Many of the new words were driven by technological change -- terms like "Instagramming," "airplane mode" and "force quit" will sound familiar to most smartphone users.

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