Grot stands for grotesque face. Grotesque faces have been used in art, architecture and furniture making for millennia. I don't know anything other than that or any myths behind it.

I wish I could see your picture MAE060669.

AAKK! Mike's website is gone. I was going to direct you to the Garden of MU I believe he had a difinition there. Well, here's one;
"Grots are mystical, fairy-like creatures who live in the forest. If you hve gone for a walk in the woods, perhaps you have even walked very close to one OR rested on one. When humans are around, they look like your average rock on the ground but in the evening, when no human is present, they pop their little bodies out of the earth and become lively little imps playing together"

Here is a link that might be useful: Grots

Sarahsaid,
I have a link now,
try this:

-Allison

Here is a link that might be useful: Hypertufa Impressions