American Heritage Dictionary says a CREST is:

crest (krRst) n.
1.a. A usually ornamental tuft, ridge, or similar projection on the head of a bird or other animal. b. An elevated,
irregularly toothed ridge on the stigmas of certain flowers.
2.a. A plume used as decoration on top of a helmet. b. A helmet.
3.a. Heraldry. A device placed above the shield on a coat of arms. b. A representation of such a device.
4.a. The top, as of a hill or wave. b. The highest or culminating point; the peak.
5. The ridge on a roof.

For a crest and seal chip, this has been discussed a lot. Take your choice:
(a) a personalized, "protected," special-order design on a chip, like in definitions #2 and #3 above. I was thinking of adding a 4th criterion for Crest and Seal chips -- that they be personalized/special-ordered/not genric. But I was convinced not to do it. For one thing, most collectors call the generic Florida Palm and Sailing Ship litho inlaid poker chips CREST AND SEAL.

(b) a promotional feature of chips where the the ridge area is thicker than the center area where the inlay is (convex,
concave business). Doing this is supposed to (1) protect the inlay (hot-stamp too) from rubbing and wearing out, and (b)
making the stack of chips more stable and easier for the dealers to "cut" if the centers of the chip don't bulge/rub against
each other. Catalogs proclaim that the "hollowed" center area creates a suction that holds the chips stacked nicely. "Speed
checks"?

ROBERT