The family Ardeidae, with 72 recognized species, are referred to as egrets or bitterns or herons in the order Pelecaniformes.
Although herons resemble birds in some other families, such as the storks, ibises, spoonbills, and cranes, they differ from these in flying with their necks retracted, not outstretched.

Ardeidae, Ardea: the Latin word ardea meaning "heron".