frass

American  

[fras] / fræs /

noun

1. insect excrement.

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frass British  

/ fræs /

noun

1. excrement or other refuse left by insects and insect larvae

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Etymology

Origin of frass

1850–55; originally, the refuse and excrement of boring or leaf-eating insects < German Frass insect damage, corrosion, noun from base of fressen to eat (of animals); fress, fret ¹

Example Sentences

But it is this strong smell, as well as the smell associated with their insect poo - frass - that makes them ideal to be found by sniffer dogs.

From BBC • Aug. 30, 2025

One example is the skipper caterpillar, which can shoot solid pellets of its waste, known as frass, over a distance up to 38 times its body length to keep predators off its tail.

From Scientific American • Feb. 28, 2023

Composted frass led to a 12% increase in plant-nourishing soil organic matter, something that otherwise declines over time, according to the company's research.

From Reuters • Jan. 30, 2023

But it will have an aesthetic benefit, and it may make sitting beneath the trees in June less repulsive by reducing the excreted frass dropping from above.

From Seattle Times • Oct. 13, 2022

Paranal forks: two lateral, bristle-like structures in some caterpillars, used to throw frass pellets to a distance.

From Explanation of Terms Used in Entomology by Smith, John. B.