Bas relief-A French term from the Italian basso-relievo ("low relief"). Bas relief is a sculpture technique in which figures and/or other design elements are just barely more prominent than the (overall flat) background.
Bas relief is created either by carving away material (wood, stone, ivory, jade, etc.) or adding material to the top of an otherwise smooth surface (say, strips of clay to stone).
This is a technique as old as humankind's artistic explorations, and is closely related to high relief.