By Emma Griffiths
'Xmas' is beloved of shop sign and headline writers
It fits neatly on shop sale signs and in headlines but the word 'Xmas' has a tendency to get people riled.
Some complain it takes the Christ out of Christmas, others assume it is a form of lazy shorthand.
Style guides at the Times, the Guardian and this website are among those which rule out its use, where possible.
But should this particular four-letter word be causing so much offence?
Researchers say it is a mistake to think of Xmas as a modern invention born on the High Street.
And far from being an irreligious abbreviation, it appears to have impeccably Christian credentials.
The 'X' is thought to represent the Greek letter 'Chi' - the first letter of the Greek word for Christ, Christos.
Bill Purdue, an Open University historian and author of The Making of the Modern Christmas is among those who support this view.
"I suppose to us it will always look like an abbreviation, but it would first seem to be an abbreviation used by clerics with a good knowledge of ancient languages," he said.
"A lot of people disapprove of it or think of it as blasphemous because they think the X stands for anonymity - the 'Mr X' sort of idea."
It seems Christmas has been abbreviated for at least the past 1,000 years.
Before Xmas, there was XPmas, according to Inge Milfull, assistant editor of etymology at Oxford English Dictionaries (OED).
She found references in the Anglo Saxon Chronicle as far back as 1021 and says the P was probably dropped later.
There may have been religious reasons for abbreviating Christ, as Jehovah was abbreviated in Hebrew, she said.
"But of course it also saved space and in a gospel manuscript the word Christ would appear lots of times. Parchment was expensive so anything that would save space would be welcome.
"And it's no coincidence that X resembles a cross - there's quite an old symbol, an X and a P, called Chi-Ro, and it could be that an X looked like a symbol for Christ."
Whatever its origins, it was good enough for the poet Samuel Taylor Coleridge, who wrote in a letter in 1801: "On Xmas Day I breakfasted with Davy".
But, along with complaints that Christmas has become too commercial, critics of the word persist - and in some cases take direct action.
The former Bishop of Blackburn, the Right Reverend Alan Chesters, made a recommendation to his clergy that they avoid using the word altogether.
Some argue 'Xmas' makes Christ anonymous
He is now retired, but the diocesan spokesman Martyn Halsall said "Xmas" was still a talking point, particularly among older people, regardless of its Greek meaning.
"I think that's a subtlety that is lost on most of the population," he said.
"As Christmas is in danger of becoming so over-commercialised people are saying: 'Let's remember what it is all about'."
A Church of England spokesman said there was no policy on using the word Xmas, and some clerics were well aware of its Greek roots and saw no problem with it.
But for Jane Wyles, deputy editor of the Church of England's C Magazine for the Diocese of Southwell, it is part of a "blasé attitude" towards Christmas which she finds offensive.
"I know Xmas has been substituted for Christmas for a long, long time but it gets my goat," she said.
"It is the glib way people substitute Christ with this anonymous 'X'. It's all part of the PC picture - Christianity gets squashed into a smaller and smaller corner."
She is also not convinced by the argument that the word's history makes it acceptable.
"It makes it a bit better but, at the same time, people aren't writing it for that reason. They are writing it for quickness," she said.
"When it comes down to it, it doesn't really matter, but it's just part of the whole degeneration of what, for me personally, is very important."