Is the term "guinea pig" defined in the Pilot/Controller Glossary? Is the term "guinea pig" now or was it previously defined in the Pilot/Controller Glossary?

If it's not defined in the Pilot/Controller Glossary, maybe it's in some other publication.

I was flying with a crew member who used it while querying ATC about threading a hole in a line of weather. It went something like, "has anyone else guinea pigged that hole?" He said it was an actual controller term in their documentation.

I can't find it, but I was wondering if there was some kernel of truth to the statement.
Being a "guinea pig" means to be the first to try out a (potentially dangerous) situation. There is no mention, past or current of the term "guinea pig" or any derivation of that.

Slang slips through on the radio, this is probably an instance of that. If the pilot or controller used that term the appropriate response would be "unclear, please say again". 

There is also no mention of it in the AIM.