"Grexit" has gone from being a word that no-one had heard, to one that people couldn't quite believe they had heard, to one that people can't stop hearing, in a very short space of time.
Google Insights  shows the search volume for the word over the last twelve months (the scale is searches, normalised so that the highest month is equal to 100):
As you can see, it was first heard in February, has a local maximum in March, and then rocketed up this month (it is likely to rise even higher in the last third of May). So where did it come from? Who do we have to blame?
It's all Citigroup's fault. On 7 February, Willem Buiter and Ebrahim Rahbari at Citi released a briefing note that read:
We raise our estimate of the likelihood of Greek exit from the eurozone (or ‘Grexit’) to 50 per cent over the next 18 months from earlier estimates of ours which put it at 25-30 per cent.
For the record, on 7 May Citi cranked up  its odds of a Grexit to 50-75 per cent. If they are better at making medium-term predictions than they are at coining words that don't sound like an antidepressant, there is still time to short the Euro.