Gouge is often used to mean a collection of "unofficial" but noteworthy info, techniques, and practices that are put in one place for easy finding. IE "Our company handbook is used procedurally, but I have another book of "Gouge" with my quick reference lists and techniques".
A gouge is where an object has run along the skin of the a/c and put a furrow in the skin without actually puncturing it. The material that has been lifted will be at either/or the sides of the furrow or at the end of it.
That's the last time I'm getting a US training manual using US slang! Geez, the 732 study notes didn't have those slangs! However I ran into a BAe Hawk manual and some high level language there too, but no such words as gouge
Bloody "ImpactInk" Grrrr....
When losing situational awareness, pray Cumulus Granitus isn't nearby !