Wags, hoodies and carbon footprint are among hundreds of new words and phrases being added to the English dictionary.
It says a wag is the wife or girlfriend of a famous sportsman, while a hoodie is a young person in a hooded top who may be seen as "a potential hooligan".
Every year, dictionaries are updated to include new words that people are using and give a snapshot of our world today.
Also included are brainfood - things to eat that make you more brainy - and new sports airboarding and chess boxing.
Global warming and the environment are hot topics at the moment so it's no surprise that carbon footprint is one of several related phrases to make it into the ninth edition of the Collins English Dictionary.
What else is in there?
Blook - A book published on a weblog
Choon - a piece of music someone likes
Exergaming - Playing video games that require a lot of physical exercise
Infomania - An obsessive desire for factual information
Mobcast - a podcast created and uploaded using a mobile phone
It's official meaning is "a measure of the amount of carbon dioxide released into the atmosphere by a company, household or individual through day-to-day activities over a given period".
But not all the new additions are so serious, for example, muffin top - meaning a roll of flesh that spills over the top of a tight skirt or trousers. Nice!