gua·​no ˈgwä-(ˌ)nō How to pronounce guano (audio)
: a fertilizer containing the accumulated excrement of seabirds or bats
broadly : excrement especially of seabirds or bats

Examples of guano in a Sentence

Recent Examples on the Web The island of Redonda was devastated in the late 18th and early 19th centuries by guano mining operations that left behind invasive black rats and goats. Cameron Pugh, The Christian Science Monitor, 14 Nov. 2023 Measuring the impact of guano may seem unglamorous—the ultimate crappy job, even—which may explain why such systems went overlooked for so long. Amy Brady, Scientific American, 17 Oct. 2023 The cave was first accessed in 1831 by the owner of the surrounding lands, who was looking for bat guano to use as fertilizer, per the study. Margaret Osborne, Smithsonian Magazine, 2 Oct. 2023 Flocks of pesky sea gulls, looking for free food, circle constantly, depositing their guano on roofs, cars and customers in nearby shopping centers. Jesse McKinley Lauren Petracca, New York Times, 17 Sep. 2023 People in the region collect bats’ guano for fertilizer, hunt them for food and—in the Solomon Islands—even use their teeth as traditional currency. Kate Evans, Scientific American, 28 Aug. 2023 Coaxing a virus that lies dormant in bat guano to grow in a cell culture is difficult, and usually the effort fails. David Quammen, New York Times, 25 July 2023 While rabies poses a rare threat, bat guano is the most serious concern. Kylie Martin, Detroit Free Press, 27 June 2023 And seabirds on Tern roam even farther, providing important services as far as the waters off California and Alaska, including fertilizing the land and ocean with their guano, thus spurring the growth of plants, coral reefs and phytoplankton at the bottom of our food web. Smithsonian Magazine, 10 July 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'guano.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Spanish, from Quechua wanu fertilizer, dung

First Known Use

1604, in the meaning defined above

Time Traveler
The first known use of guano was in 1604

Dictionary Entries Near guano

Cite this Entry

“Guano.” Dictionary, Merriam-Webster, Accessed 3 Dec. 2023.

Kids Definition


gua·​no ˈgwän-ō How to pronounce guano (audio)
: a substance composed chiefly of the excrement of seabirds or bats and used as a fertilizer

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