According to the Oxford dictionary, the word "trialogue" has been around since the sixteenth century, and is defined as a "dialogue or meeting between three people or groups".
The spelling without an 'a' is also accepted, and a "trilogue" is, according to PhD candidate Alexander Hoppe, now the preferred spelling when describing the three-way informal law-making negotiations between European Commission, European Parliament, and the Council of the EU.
But when Hoppe recently received one-page essays from his students about trilogues, he saw "such a wide range" of varieties in spelling the word.
"It doesn't help that the spell checker automatically changes it into trilogies," said trilogue-researcher Hoppe in an interview with EUobserver.
Trilogues have become the de facto way of resolving differences of opinion between the EU institutions about how new EU directives and regulations should look.
In behind-closed-doors meetings, representatives of the three institutions come together in sessions which sometimes last until the early morning of the next day.
Last year, EUobserver revealed that in 2016 not a single bill ended up in a public second reading – the traditional route for a legislative proposal – but went to trilogue instead.
Despite the importance of trilogues in EU law-making, they are mostly out of the public eye.
Hoppe, a German working at the University of Utrecht in the Netherlands, said he only ever talks about trilogues with friends when they ask him about his work.
"But it is not something anybody outside the EU bubble has ever heard of," he said.
Little research has been done into how trilogues work – in part because the lack of transparency make it so hard to research them. Hoppe is part of an international research network that is trying to lift the lid.
Trilogues are notoriously opaque and raise the question how democratic they are.
"That's a difficult question. The question is: what is the alternative?"
"If in an ideal world societal interest is represented in these trilogues to a fair share, and if all the actors in the European parliament and the council that want to know something about how the negotiations proceed [can], then I don't think it's necessarily problematic. But we don't know that," said Hoppe.
"That's one reason for our research project: that I don't know how harmful it is for democracy, or whether it is just a more effective but still democratic way of making legislation," he added.
But he also noted that transparency is not the only indicator to determine the quality of a democracy – and that the focus on transparency is much bigger for EU legislation compared to national law-making.
"Let's face it, national lawmakers work in more or less similar ways," he said.
"Many things that are highly criticised in EU politics, happen similarly in national politics, but they are not really looked at. That's of course a trust issue – that's the only explanation I have for this," said Hoppe.
"If you trust your institutions, then you also accept more that they do things behind closed doors," he added.
The German PhD candidate is researching what happens during the trilogue meetings.
"What is the negotiation dynamic? Is it bargaining, problem-solving? When do people decide on what? When are compromises stuck, at which administrative hierarchical level?"
The research project started in September 2016 and will last for three years.
Much of the theoretical work has been done, Hoppe said on a recent visit to Brussels.
"Now we really start digging into the cases. That's also why I'm here now, to have the first interviews. Now the fun work starts," he said.
One thing Hoppe has already learned is that there is no typical case of trilogues.
"That is of course what we are after as researchers: we want typical cases. That seems not to exist. There is a huge difference in conducting trilogues from committee to committee," he said, referring to the thematic committees in the EU parliament.
A key document type in the trilogue talks is the 'four-column document', which lists the positions of the three institutions on every contentious paragraph of the proposed bill.
Hoppe found out that they are not stored centrally and that there is no single format.
"Many have the draft compromise text in the fourth column, but others just have some instructions to the negotiators," he said.
The number of people in the negotiating room can also vary, from around forty up to a hundred.
There is some evidence to suggest that the organisational set-up has been used as a negotiating tactic as well.
"There is not a specific room [where trilogues are held]. Normally it is in one of the EP buildings. Because it is the EP committee that normally has the organisational responsibility," said Hoppe.
"In the beginning apparently the committees used to have the committee chair sit above the rest," he added.
Another insight Hoppe found is that - among the people involved in trilogues - they are not controversial.
"Nobody has ever said there would be an alternative to trilogues. It is very clear that they are very accepted and wanted in the institutions," he said.