Prominent commentators such as Paul Krugman, the Nobel-winning economist who writes for the New York Times, helped propel the term into the mainstream.
The gist of the "This is a coup" epithet is that eurozone countries -- particularly a bloc led by fiscal hawks Germany and Finland -- have crafted a take-it-or-leave-it proposal that requires Greece to enact measures effectively putting its economy under their control.
The measures, per an early draft circulated to the media, tell Greece to hold parliamentary votes between Monday and Wednesday passing tax and pension reforms, put 50 billion euros ($55 billion) of state assets in escrow under European supervision as collateral, and promise to follow through with far-reaching shake-ups to its labour market and effect privatisations.
If it refuses, Greece is to be forced out of the eurozone in a "Grexit", which would devastate its already collapsing economy.
Twitter users expressed their rage from Greece to Britain.
"Germany is destroying Europe once again," Tweeted @KostasKainakis, whose profile says he is a marketing lecturer in Athens.
"The Germans could not do it with tanks so now they try it with banks Trying to STEAL Greek assets BrITS MUST vote to get out," opined a tweet from Britain by @AllanSkerratt, who said he was a non-partisan retired soldier and ex-teacher.
Krugman, in the New York Times, said: "The trending hashtag #ThisIsACoup is exactly right. This goes beyond harsh into pure vindictiveness, complete destruction of national sovereignty, and no hope of relief."