You've probably seen them gathered around dumpsters and in parking lots- homeless cats that flee from humans. These domestic cats, that are referred to as "feral", are the result of both the failure to spay/neuter and cat abandonment.
The only difference between a housecat and a feral is that the latter has had little or no human contact and developed a natural fear of humans. Ferals are erroneously labelled as "wild cats". A bobcat is a wild cat: a feral cat is a homeless domestic cat.
The word "feral" is used to describe a homeless domestic cat that is afraid of humans. As with any frightened animal, it is very important to use extreme caution. Always consult with an experienced rescuer before attempting to handle or trap a feral cat.