'Feral' refers to something more than just the behavior of a domestic animal when it is outdoors away from humans. Feral animals are of a species that has been bred for domestication, but which are not themselves domesticated.
A feral cat is one that has grown up without human contact, and they cannot be kept as pets because they never learned to live closely with humans. When Animal shelters are notified of large populations of feral cats, they generally gather them up, spay and neuter them, take any kittens away (as they can still be raised as pets) and re-release them, either in the same location, or on the property of someone willing to have them (a farmer perhaps).
Domestic cats raised by humans, do make lots of noises that feral cats do not, because they are noises we reward with food and attention.
Fun fact: The pigeons found in US cities are actually feral descendants of versions of domesticated rock doves.