fecal material and/or wood shavings produced by insects.
Merriam-Webster Online Dictionary
frass (noun) debris or excrement produced by insects
frass (Wikipedia)
Frass in the oak leaf mine of a final instar larva of the moth Ectoedemia heckfordi
![](http://upload.wikimedia.org/wikipedia/commons/thumb/4/4d/PACIFIC-DAMPWOOD-TERMITE-Zootermopsis-angusticollis-frass-4000x2200_1.jpg/220px-PACIFIC-DAMPWOOD-TERMITE-Zootermopsis-angusticollis-frass-4000x2200_1.jpg)
The frass of dampwood termites may be a useful sign of an infestation
![](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Starr-101228-5860-Prosopis_pallida-dust_frass_from_Bostrichid_beetle-Lua_Kealialalo-Kahoolawe_%2824763389590%29.jpg/220px-Starr-101228-5860-Prosopis_pallida-dust_frass_from_Bostrichid_beetle-Lua_Kealialalo-Kahoolawe_%2824763389590%29.jpg)
Typical frass dust from Bostrichid shot hole borer beetles
![](http://upload.wikimedia.org/wikipedia/commons/thumb/0/03/GTB_larva_P1060034.jpg/220px-GTB_larva_P1060034.jpg)
A golden tortoise beetle larva carrying a mass of its own frass as a repugnatorial defence.
Frass refers loosely to the more or less solid excreta of insects, and to certain other related matter.