What is gnurr?

The sound a dog makes when he can't quite make it to a growl, but wants others to know he is sleeping in the area?

this is all I actually found. you are on your own.
Chiquita
gnurr. - The substance that collects over time in the bottoms of pockets or cuffs of trousers. See also related terms for pockets. Farlex Trivia Dictionary. © 2012 Farlex, Inc.
Gnurr - definition of gnurr by The Free Dictionary [ http://www.thefreedictionary.com/gnurr_green]
www.thefreedictionary.com/gnurr

Very tiny lint fibres from cotton, linen and wool that builds up in pockets, as described in the below link - but I do like that doggy definition

https://en.wikipedia.org/wiki/Lint_(material)#Pocket_lint