The Killer Whale is considered a type of dolphin.

True. The killer whale, or orca (Orcinus orca), is considered a type of dolphin. Despite its common name including the term "whale," the killer whale is the largest member of the dolphin family, Delphinidae. Dolphins and killer whales share similar characteristics, such as their streamlined bodies, intelligence, and social behavior. Taxonomically, both dolphins and killer whales belong to the family Delphinidae within the order Cetacea. The term "whale" is often used loosely to describe any large marine mammal, but killer whales are, in fact, more closely related to dolphins than they are to true whales like baleen whales or sperm whales.