Definition of "ululation"

The overthrown Martian set up a prolonged ululation, and immediately a second glittering giant, answering him, appeared over the trees[.]

1898, H.G. Wells, The War of the Worlds, London: William Heinemann, page 137

As we started there broke from the thick silent woods behind us a sudden great ululation of the ape-men, which may have been a cheer of triumph at our departure or a jeer of contempt at our flight.

1912, Arthur Conan Doyle, The Lost World […], London, New York, N.Y.: Hodder and Stoughton

Because it is not as reliable as the simple ululation or the louder cross-register ululation, it should be allowed a certain amount of preparation time.

1980, Deborah [Helene] Kavasch, An Introduction to Extended Vocal Techniques: Some Compositional Aspects and Performance Problems (Reports from the Center (University of California, San Diego, Center for Music Experiment); vol. 1, no. 2), La Jolla, Calif.: Center for Music Experiment, page 6

Maryam, my research assistant, and I were going through some interviews we had conducted the previous day, when cheerful ululation disrupted our discussion. Coming from the culture of north Sudan, where such ululation may announce the happy news of a wedding or a circumcision, I assumed a similar situation was taking place […]

2007, Amal Hassan Fadlalla, “Gendered Placenta: The Paths to Proper Fertility and Responsible Motherhood”, in Embodying Honor: Fertility, Foreignness, and Regeneration in Eastern Sudan, Madison, Wis.: University of Wisconsin Press, page 109

[T]he sound of the ululation brought my own past and future, my entire life, in front of my eyes like a very long road, and it was as if this ululation was reaching the ear from its most distant and shadowy edges. This is how my day began.

2014, Rabindranath Tagore, translated by Rosinka Chaudhuri, Letters from a Young Poet: 1887–1895 (Penguin Modern Classics), New Delhi: Penguin Books

The Queen had heard ululation many times in the past as she travelled the world, particularly in Africa, but this time, the sound made her shiver. Ululation is found in some singing techniques and ritual situations.

2014 August 20, Peter Ship, “April–May”, in McNiven: The Kingdom Guardian, [Bloomington, Ind.]: Xlibris, page 198