The nymphs of Greco-Roman mythology are typically depicted as beautiful, young maidens of marriageable age. The term nymph literally means "bride". They are usually subdivided into categories by dwelling and association. For example Oreads (nymphs of the mountains), Dryads (nymphs of the trees), Naiads (nymphs of fresh water). The Nereids and Oceanids, feminine nature spirits of the seas, derive from similar concepts and might also be called nymphs.
There are several legends of nymphs mating with gods and mortals, giving birth to notable offspring. Others simply depict them as companions to major deities, such as Artemis.