I recently stumbled over this wiktionary page: https://en.wiktionary.org/wiki/parc#English
parc (plural parcs)
Alternative form of park (partially enclosed basin in which oysters are grown)
I found another source (based on Oxford dictionary) that has this to say:
The total number of vehicles considered collectively; the vehicle population.
When I search for the word "parc" in Merriam-Webster, I don't find anything. Yet it seems that this term is sometimes used.
For example, Parc Cynog is a wind farm operated by Nuon Renewables in Wales (source)
So now I'm really curious what the difference is between those two spellings.