The only widely recognized dolphin–false killer whale hybrid is called a wholphin. The best-known wholphins are hybrids of a female common bottlenose dolphin and a male false killer whale, even though both parent species belong to the oceanic dolphin family.
The name is a portmanteau of “whale” and “dolphin,” reflecting the false killer whale’s misleading common name. False killer whales are not true killer whales; they are large dolphins in the genus Pseudorca. Their hybrid offspring therefore combine traits from two related but very different-sized oceanic dolphins.
The first recorded captive wholphin was born in Tokyo in 1981 and survived for about 200 days. The best-known surviving individual, Kekaimalu, was born at Sea Life Park in Hawaii in 1985. She later produced offspring, demonstrating that at least some wholphins can be fertile.
“Wholphin” is sometimes used more broadly for other rare toothed-whale hybrids, including hybrids involving melon-headed whales or rough-toothed dolphins. In ordinary trivia usage, however, it refers to the famous false killer whale–bottlenose dolphin hybrid. “Porpoise” is a separate biological term, not the name of this hybrid.