It's Carl Von Linné who first named this animal the Delphinus Orca in 1758. In 1860 it was placed in a new category Orcinus Orca. The origin of this word is uncertain. It is thought that it comes from the Latin Orca "a race of whale" and from the Latin Orcynus " a kind of tuna". However some think that the word comes from Orca, name given to the container used by Roman to transport liquid and which shape is similar to the killer whales'. Others believe that the origin is Orcus, a hellish deity from Antiquity.

MAMMAL:

Vertebrate animal having mammae, with a skin generally covered with fur (except for cetacean), with a 4 cavities heart and a relatively developed brain. Reproduction is nearly always viviparous.

Sub class of mammals having a prolonged intra uterine foetus development, associated with a placenta. The eutherian are also called placental or monodelphi.

Comes from the Greek Ketos (large marine animal). Mammal order pisciform, aquatic and carnivorous. The anterior limbs have become fins and the caudal is powerful and horizontal. This order comprises the sub order odontoceti (with teeth) and mysticeti (with baleen). This order has 78 known species of whales, dolphins and porpoises.

Comes from the Greek ODOUS, ODONTOS, tooth and KETOS.
Sub order of cetacean with cone shaped teeth that do not regenerate. Their nostril is unique and dorsal.

Odontoceti cetacean family. Streamlined swimmer, powerful and living in all the oceans and seas of the globe. Their mouth/nose is stretched out (except for the killer whale). There is about 32 species of dolphins grouped in this family.

Classification of the killer whale is fairly difficult as some recent studies show that they could be several species of killer whale. It is possible that in few years time, a new sub family could be created. For the time being, the International Whale Commission only recognise the ORCINUS ORCA in the Atlantic Zone and the ORCINUS RECTIPINNA in the Pacific Zone. However, in 1981, a Russian scientific team has discovered a smaller specie called ORCINUS NANUS. In 1982, another Russian team has studied a new group in the Antarctic Zone called ORCINUS GLACIALIS. It seems though, that NANUS and GLACIALIS are the same specie of a dwarf killer whale.
A NEW SUB FAMILY COULD BE BORN: ORCINICES.