The answer is both! Orcinus orca is the Latin scientific name, while killer whale is its common name. Scientists interchangeably use orca and killer whale.

Our past relationship with orcas has not always been as favorable as today. Beginning with Orcinus—a god of the underworld—they’ve since been known as devilfish, assassin whale, wolves of the sea, and whale killers, which sometime later was flipped to killer whales.

Orcinus orca was first used in 1758 by Swedish naturalist Carl Linnaeus, who developed a system for classifying plants and animals that’s survived to the present day. Classification helps us understand relationships between organisms, and shared characteristics— and this is what places orcas in the dolphin family.