Acorn-shaped refers to something that is shaped like an acorn, which is a small, oval nut that grows on an oak tree. Some synonyms for acorn-shaped include ovoid, egg-shaped, elliptical, oblong, and fusiform. Ovoid refers to a shape that is rounded and slightly elongated, similar to an egg. Egg-shaped is self-explanatory, describing something that is shaped like an egg. Elliptical refers to a shape that is like an oval, but has more of a flat edge. Oblong means something that is longer than it is wide, with straight sides. Finally, fusiform refers to a shape that is tapered at both ends, like a spindle.