- a transparent or translucent gemstone with a pearly luster; some specimens are orthoclase feldspar and others are plagioclase feldspar
- Moonstone aka Meteorite aka Ms. Marvel (real name Dr. Karla Sofen) is a fictional character, both a supervillain and superheroine in Marvel Comics' Marvel Universe.
- Moonstone is a Japanese visual novel studio known for creating adult-oriented bishojo games. The founding members of Moonstone had once been members of Circus, a similar visual novel studio.
- A pearly white semiprecious stone consisting of alkali feldspar
- An oval playing field or racing track
- In technical drawing, an oval (from Latin ovum, 'egg') is a figure constructed from two pairs of arcs, with two different radii (see image on the right). The arcs are joined at a point, in which lines tangential to both joining arcs lie on the same line, thus making the joint smooth.
- ellipse: a closed plane curve resulting from the intersection of a circular cone and a plane cutting completely through it; "the sums of the distances from the foci to any point on an ellipse is constant"
- A body, object, or design with such a shape or outline
- egg-shaped: rounded like an egg
- An act of causing a bell to sound, or the resonant sound caused by this
- Each of a series of resonant or vibrating sounds signaling an incoming telephone call
- A telephone call
- a characteristic sound; "it has the ring of sincerity"
- sound loudly and sonorously; "the bells rang"
- a toroidal shape; "a ring of ships in the harbor"; "a halo of smoke"