There are lots of different types of flowers we call daisies. There's common daisies, African daisies, and Shasta daisies, to name a few. In fact, there's a whole family of plants that is known as the daisy family. The more scientific name for that family is Asteraceae.
The Asteraceae family is divided into smaller groups, one of which is the Gerbera genus. Any flower in the Gerbera genus could be called a gerber daisy. But usually when people use that term, they're thinking of the species Gerbera hybrida.