It is a neologism taken from English, which at some point is going to be Castilianized. It describes a huge mass of grease-glued garbage that floats in the sewage drains of cities and ends up clogging the filters of water treatment plants, if not ruining the suction pumps. The name is the combination of the English fat ("fat") with iceberg (áisberg "mass of ice large as a mountain that floats adrift in the seas") which is used in Spanish and has Germanic origin. See azolve, iceberg.
