In the day, any chip with an inlay was called by the manufactuers (USPC or Burt) crest and/or seal, or seal and/or crest. However that definition was way too broad for collector. Such a definition would consider molded chips (hat & cane, H-mold, large key, etc) crest & seals if they had inlays.

For collecting purposes, clay, plain mold chips with inlays are c&s. I also add that chips should be antique (50+ years old) and custom made (with 1 or 2 exceptions). Also, the inlays should have some kind of print or a litho on the inlay.

I don't consider Skips chips to be c&s for a couple of reasons: 1, there is no litho or other type printing on the inlay, 2, they are generic, 3, they are what we call generic die-cuts. Most c&s have solid round inlays.

Steve Passalaqua is the die-cut maven although his interest lies in custom made die cuts not generics.