Grids, without -s, would be a backformation:Originally Posted by Lewis
Gridelet => Grid
But given that -s is not part of the name, that it's been added, Grids is most likely a diminutive suffix. Click here to read more about Diminutives in Sports. Grids is the diminutive of, or term of endearment for Gridelet.
As for the French phrase Pas De Deux, it's listed in the Oxford Dictionary of Current English; i.e., a dance for two, which makes it a borrowing, or a phrase borrowed (into English) from French.