To ululate is to loudly howl or wail. Animals ululate, and so do people in pain.
This is an unusual-looking word, but it means something easy to understand: howling or wailing loudly. A lion will ululate. A person in pain will ululate. Coyotes and wolves — who are known for their howling — ululate. People who have their hearts broken might cry and ululate. Ululating could mean the animal or person is in pain, or maybe they’re trying to communicate something else. The key element is that it’s loud.