Origin the Name

The name is from Ancient Greek δελφίς delphis meaning "with a womb" which can be interpreted as meaning "a 'fish' with a womb".

The word is used in a few different ways. It can mean:

• Any member of the family Delphinidae (oceanic dolphins),
• Any member of the families Delphinidae and Platanistoidea (oceanic and river dolphins),
• Any member of the suborder Odontoceti (toothed whales; these include the above families and some others),
• Used casually as a synonym for Bottlenose Dolphin, the most common and familiar species of dolphin.

In this article, the second definition is used. Porpoises (suborder Odontoceti, family Phocoenidae) are thus not dolphins in this sense. Orcas and some closely related species belong to the Delphinidae family and therefore qualify as dolphins, even though they are called whales in common language. A group of dolphins can be called a "school" or a "pod".