A feral cat is typically born and raised in the wild, or who has been abandoned or lost and reverted to wild ways in order to survive. A feral cat will not attempt to interact with or be in close contact with humans. If a human approaches, like any wild animal, they will run away.
A stray cat is a cat that has been in close contact with humans and had been abandoned or lost. These cats are often friendly and will interact with humans when approached.