What is the nostril of a killer whale called?

The orca (killer whale) is a toothed whale and is the largest member of the Dolphin family. These marine mammals are easily distinguished by their black-and-white coloration, large dorsal fin, and sleek, streamlined body. Killer Whales have lungs and they breathe air (like humans). But instead of breathing through their mouth, they breathe through their nostrils, called blowholes, located on top of their heads.

Source: Nature Mapping