Run into it a lot reading a cryptozoology site.
I know it means “supernatural” basically,but can’t find it in any dictionary.
“Fortean” comes from the name Charles Fort. Fort was a pioneer in cataloging strange phenomena, rains of frogs and the like. There is (or was) a magazine called “Fortean Times” dedicated to continuing his reporting. The name has come to refer to any natural phenomena which does not seem to have a logical or scientific explanation.
In addition to the definition given above, the term is often given to a good many anomalous and apparently inexplicable occurences which are outside the realm of natural phenomena, being instead human artifacts. For instance, Charles Fort cited numerous instances in his writing of man-made objects being found in unexpected places, such as Asian sculptures turning up in excavations in Ireland.
In practice, a lot of “forteana” seems to consist of material which is cited as being inexplicable because an enthusiast has not, or will not, seek an explanation. For instance, some years ago I read of a massive steel sructure (IIRC, it looked sort of like a gigantic hair curler), found adrift in the North Sea. As no government, and no industrial concern, would admit having lost it, it was held up as “forteana”.
Alternatively, the possiblity that a government, or a company working on a government contract, lost a piece of prototype equipment it did not wish to discuss immediately suggests itself. A number of countries–the U.S. included–have been known to violate arrms agreements from time to time. If a piece of prohibited research, or a perfectly lawful development in spy technology–were lost at sea, it seems likely the responsible party would be loath to admit it. While this seems more plausible than the assumption that such a find must be a mysterious artifact from a parallel reality, such mundane considerations tend to get overlooked in Fortean literature.
People have even gotten sort of conditioned to assume the inexplicable. Back in the early 70s, I recall, a ridiculous amount of publicitiy was given briefly to a “mysterious” steel sphere which turned up somewhere or other in the rural United States. Eventually it was given to a board of experts assembled by The National Enquirer. While all sorts of mystrious claims circulated about it for a while–such as that it would roll of its own accord to the four corners of a table and then roll back to its starting point–it turned out to be something quite mundane; IIRC, a piece off a piece of oil equipment.
Similarly, around 1990 the local media in St. Louis became alarmed and fascinated when a jar containing a mysterious, unidentifiable “thing” was found in a field. After a few days the alien mostrosity, unknown to mortal science, turned out to be a wine “mother”; a fungus used by winemakers to speed fermentation. SOme local amateur winemakers complained that it had been stolen off of their porch.
The fortean outlook has been a help to the advancement of knowledge in that encourages people to take notice of the anomalous and have an interest in it. It has been a hindrance in its reflexive assumption that every mystery is a great impenetrable mystery. To their credit, the people at Fortean Times tend to be open to mundane answers, and to be skeptical about their own skepticism–something Charles Fort claimed to be, and sometimes was.