The definition of frass is the waste left as an animal's bowel movement.
An example of frass is what a bug excretes after eating a leaf.
Debris or excrement produced by insects.
The mixture of fecal material and plant matter left by an animal, esp. an insect, after it has eaten its way into a tree, plant, etc.
Origin of frass
- German feed, result of eating, insect damage from Middle High German vrâz from Old High German frāz from frezzan to eat ed- in Indo-European roots
From American Heritage Dictionary of the English Language, 5th Edition