The word Poltergeist, German for "noisy ghost," is now commonly used to just mean a ghost; but the word is actually more a description of a type of paranormal event rather than any sort of paranormal being. The term was originally coined in the early 1800's in Europe to describe situations in which it appeared that many physical effects were being caused by non-physical entities. In general, 'poltergeist' describes situations in which inanimate objects move, break, appear, and disappear with no apparent interaction with a normal cause for these effects. When these events happen, they are often attributed to a supernatural source, such as ghosts, demons, and aliens; less commonly, scientific or psudo-scientific explanations are put forward... but in all cases the activity itself is what is described as a 'poltergeist.'
The oddities attributed to poltergeist often defy normal scientific laws for motion and inertia. Objects are seen floating slowly across rooms, or taking 90-degree turns in mid-flight, slow or not. Objects apparently thrown can impact with no force at all, as if they were never moving... and objects sitting still can suddenly accelerate and smash against walls. Rocks have been seen to literally appear from nowhere near ceilings to rain down into rooms, and fluids have done the same, leaving no mark on or in the ceiling to indicate any form of contact or passage. Loud explosions and breaking sounds issue from the air, with nothing actually damaged... and objects are discovered smashed to pieces moments after being seen intact, with no noise having been generated.
Many researchers began to study poltergeist activity as a general topic in the 1960's and 1970's, because it appeared to be an area of paranormal study that might be scientifically tested and someday understood... but no clear answers have been found, in part because poltergeist activity is also the easiest paranormal event for amateurs to fake. Due to concentration through the 70's and 80's both research-wise and in movie and TV entertainment on poltergeist effects that focused around one young person, many people now assume the very word 'poltergeist' means 'ghostly activity centered around a young person, presumably psychic'... which is a further confusion of the word's meaning and use.
Due to the general nature of this topic, below I list all events in Anomalies that feature some form of poltergeist activity; and I also will list separately known cases of faked poltergeist activity. After all, you have to know what to watch out for if you're interested in researching real poltergeist activity, right?