Many shapes have metaphorical names, i.e., their names are metaphors: these shapes are named after a most common object that has it. For example, "U-shape" is a shape that resembles the letter U, a bell-shaped curve has the shape of the vertical cross section of a bell, etc. These terms may variously refer to objects, their cross sections or projections.
Types of shapes
Curves
The Fish bladder is the intersection of two congruent disks, each centered on the perimeter of the other
Tomahawk curve, with its handle and spike thickened
Some of these names are "classical terms", i.e., words of Latin or Ancient Greeketymology. Others are English language constructs (although the base words may have non-English etymology). In some disciplines, where shapes of subjects in question are a very important consideration, the shape naming may be quite elaborate, see, e.g., the taxonomy of shapes of plantleaves in botany.
Biconic shape, a shape in a way opposite to the hourglass: it is based on two oppositely oriented cones or truncated cones with their bases joined; the cones are not necessarily the same
Geoid (From Greek Ge (γη) for "Earth"), the term specifically introduced to denote the approximation of the shape of the Earth, which is approximately spherical, but not exactly so
Heart shape, long been used for its varied symbolism
Hourglass shape or hourglass figure, the one that resembles an hourglass; nearly symmetric shape wide at its ends and narrow in the middle; some flat shapes may be alternatively compared to the figure eight or hourglass
