guano

American  

[gwah-noh] / ˈgwɑ noʊ /

noun

1. a natural manure composed chiefly of the excrement of sea birds, found especially on islands near the Peruvian coast.

2. any similar substance, as an artificial fertilizer made from fish.

---

guano British  

/ ˈɡwɑːnəʊ /

noun

1. 1. the dried excrement of fish-eating sea birds, deposited in rocky coastal regions of South America: contains the urates, oxalates, and phosphates of ammonium and calcium; used as a fertilizer

   2. the accumulated droppings of bats and seals

2. any similar but artificial substance used as a fertilizer

---

guano Scientific  

/ gwä′nō /

1. A substance composed chiefly of the dung of sea birds or bats, accumulated along certain coastal areas or in caves and used as fertilizer.

2. Any of various similar substances, such as a fertilizer prepared from ground fish parts.

---

Etymology

Origin of guano

First recorded in 1595–1605; from Spanish: “fertilizer, dung”; Latin American Spanish huano “dung,” from Quechua wanu “dung for fuel, fertilizer”

Explanation

Guano is bird or bat poop. If you park your car near the harbor, your windshield may end up covered in seagull guano. Ew. You'll most often find the word guano used for the specific bird (or bat) manure that's used as a fertilizer in gardens. In fact, the term is so common that some fertilizers are called guano even when they don't contain actual bird poop. Guano, a Spanish word with Quechua roots, is rich in nitrogen, potassium, and other nutrients that help plants grow.

Example Sentences

"Guano was a highly sought-after resource the Incas would have wanted access to, playing an important role in the diplomatic arrangements between the Inca and the Chincha communities," Dr. Bongers said.

From Science Daily • Mar. 7, 2026

Guano produced from breeding bird colonies provides nutrients for marine invertebrates and fish, for instance.

From Los Angeles Times • Feb. 25, 2024

Guano duty: How Rudy Giuliani’s ex-publicist described her job.

From Washington Post • Feb. 4, 2021

But unlike the Guano Islands, T-3 was temporary—it would melt away in the 1980s—so under international law, no nation could claim it.

From Slate • Jul. 15, 2020

We are poor; we can afford to keep but few cattle; Guano, Phosphate, Bones, Lime, etc., are beyond our means.

From What I know of farming: a series of brief and plain expositions of practical agriculture as an art based upon science by Greeley, Horace

Related Words

• compost
• droppings
• dung
• excrement
• mulch