"They both just reply 'meh' and keep watching TV," said Cormac McKeown, head of content at Collins Dictionaries.

The origins of "meh" are murky, but the term grew in popularity after being used in a 2001 episode of The Simpsons in which Homer suggests a day trip to his children Bart and Lisa.

The dictionary defines "meh" as an expression of indifference or boredom, or an adjective meaning mediocre or boring. Examples given by the dictionary include "the Canadian election was so meh".

The dictionary's compilers said the word originated in North America, spread through the internet and was now entering British spoken English.

"This is a new interjection from the US that seems to have inveigled its way into common speech over here," McKeown said. "Internet forums and email are playing a big part in formalising the spellings of vocal interjections like these. A couple of other examples would be 'hmm' and 'heh'."