The Obama campaign is running on women's issues for a third day in a row, but this has been its most successful day yet. Attempting to encapsulate what it claims to be Mitt Romney's shifting positions on a number of issues, the president's team has hit on a catchy phrase: "Romnesia".

Obama unveiled the new noun during a speech to students at George Mason University in Fairfax, Virginia, claiming that Romney had forgotten earlier positions in which he had opposed equal pay for women and easily-available contraception and had supported outlawing abortion.

The potency of the phrase was evident in the response of the audience, which laughed and cheered on first hearing on it and as Obama riffed on it in the remainder of his speech.

It quickly became clear "Romnesia" was not just a throwaway line, as the Obama campaign followed up within minutes. Obama's campaign manager, Jim Messina, tweeted that Obama "diagnoses Romney's failure to recall his extreme stances on women's issues".

The phrase instantly stuck on the social networks too. Within a couple of hours of Obama using it, #Romnesia was the third-most discussed Twitter term in the US.

A common theme was rewarding whoever came up with the term...

While others quickly embraced the opportunity to slam Romney's flip-flopping record.

The Democratic Party of Virginia was quick to seize on the remark – posting a picture of Obama in full #Romnesia mode to its Facebook page, although as it turned out, a number of people had claims to the coining of the witticism.

As far back as August, Twitter user @Ish was posting about Romneysia – which appears to be a similar ailment to the one Obama described.

While @anaheimboynxd also had a claim, as did @KawaiiMagpie:

Obama's campaign was offered an opening to attack Romney over women during Tuesday's debate, when the former Massachusetts governor made his odd remark about having looked through "binders full of women" when he wanted to achieve some gender balance in his cabinet. That phrase made Romney sound out of touch with contemporary society and the changes that have been taking place in the workplace and in attitudes towards women's rights.

In Virginia, Obama pressed home the message. Romney said he was for equal pay but refused to sign a bill that protects equal pay for equal work. Romney had said he was in favour of access to contraception but supported legislation that would allow employers to deny it. Romney had said he would protect women's right to abortion but had said earlier this year he would sign a law outlawing the right to choose in all cases.

Romney is paying the price for having to move to the right during the Republican primaries and caucuses earlier this year, in order to win over over conservatives for whom abortion remains a top issue. Up against opponents such as Rick Santorum, who has an unyielding position on abortion, Romney was in trouble, having adopted a liberal position on the issue while fighting to become governor of liberal-leaning Massachusetts. In the primaries and caucuses, Romney shifted to the right, saying in one debate that he would be delighted to support legislation outlawing all abortion.

The Obama campaign is running hard on the issue because women could hold the key to the election. Democratic candidates normally hold a lead over their Republican rivals among women and Obama has long enjoyed a lead of eight to nine points over Romney among likely women voters, compensating for Romney's lead among white males. But some polls have shown that lead eroding and the Democrats need those wavering women voters back.