Of all the rivers of words written and spoken of the missing plane, for the waiting families one is primary. Hope. Their sentences are littered with it: Hope they are alive. Hope they will come back. Sometimes it is all that is left, this thread, slim and frayed, which humanity hangs on to.
Hope is powerful yet tenuous, there is proof from the past that it is worth hoping, yet it is also an emotion that doesn't always lend itself to logic or reason.
Five years after SilkAir Flight 185 crashed into the Musi River in Indonesia in 1997, a woman still clung to the hope that her husband was alive. She believed he had lost his memory and was wandering somewhere in Indonesia but would eventually find his way back home.
Dr Tan Chue Tin, who tells this story, is a psychiatrist in private practice in Singapore who has worked with people who have lost people they love in plane crashes and the Hotel New World collapse in 1986.
"When you don't see the body," he explains, "there is no closure. This prolongs the grief process and adds to the denial they experience. The hope that their loved ones are still alive is magnified in such instances and this hope brings them comfort."
In the Atacama desert of Chile in 2010, the area where relatives gathered as they waited for their men trapped in the mine was named Campamento Esperanza. Camp Hope. Its equivalent is found in hotels and homes in Kuala Lumpur, Beijing, India, Australia and elsewhere, where the families of the passengers and crew of MH370 wait.
There is wreckage of some sort, they say, out there in the ocean off Australia. But we cannot say this is hope, that yes, finally, a plane missing for too long may be found. Debris, after all, crumples hope. As the partner of one of the passengers said on television, "I hope it's not" the plane.
Hope is clung to because it's natural and occasionally it pays off in a way that makes us consider luck and the miraculous. In 1972, a flight crashed in the Andes on Oct 13, yet on Dec 20 - 69 days later - two passengers who went looking for help found it and many were rescued.
Alongside hope always sits grief and, in a world beset by accidents, grief can't be compared for loss has no measurement. There is no set scale for tragedy, no degree for sadness, but this much is true of this plane: it is the ambiguity - how it disappeared, where it disappeared - which is crippling for families.
The miners in Chile could not be found for 17 days, then contact was made and the hope was that they would return from their subterranean bunker to the surface. With MH370, much like a missing child, or an Alzheimer's patient who wanders out with no map in his head of how to come home, there is a different inhumanity at work. In death there is loss, but this about the lost.
As Ms Clare Yeo, the Institute of Mental Health's head of psychology, said: "The relatives' lives are in limbo. If you know the person is dead, you can move on and the grieving process can start. But now they can't go back to their normal routines. They don't know what to do and what will happen next."
It is the waiting that corrodes - minutes drifting into hours into two weeks - and also the absence of any conclusion. Said Ms Yeo: "No one can give them a rational and reasonable answer and this uncertainty is very distressing."
Official updates trickle in for no one can be callous with offering hope, but on the Internet theories flourish, sightings are claimed, speculation uploads.
With the world playing detective, a morbid guessing game impacts those who wait. One moment hope, next deflation, optimism at breakfast, despair by lunch. On it goes, making absurd demands on the human spirit.
As Dr Tan said: "The mind conjures up all kinds of scenarios when you have nothing concrete. The mind just needs to find an explanation to relieve the pain and anxiety. Right now, the relatives would believe anything that suggests that their loved ones are still alive."
At the centre of it all is the frustration that in a connected age - where movies tell us satellites can tell the number plate on a car - a plane can be lost. The world is bigger than anyone thought and evidently more cruel. Perhaps, in some ways, the wreckage - if there is some - of this crash does not lie only in the sea, or on a mountain, or a plain, but also in the rooms and minds of the waiting.
Still, they wait, even as everything remains so unknown. Faith persists and it is a form of courage. As the daughter of the plane's chief steward, Mr Andrew Nari, tweeted one day: "Daddy, Liverpool is winning the game. Come home, so you can watch the game! You never miss watching the game. It's your very first time. :')"
Later, she tweeted:
"It's late midnight. I can imagine him standing at the stairs saying, 'Don't sleep late okay'. Sigh.. Goodnight, daddy. :') x"
She waits for a word and lives by one. Hope.