in antiquity, a quoit made of stone, iron, or copper, five or fix fingers broad, and more than a foot long, inclining to an oval figure, which they hurled in form of a bowl, to a vast distance, by the help of a leathern thong tied round the person's hand who threw it, and put through a hole in the middle. Homer has made Ajax and Ulysses great artists at this sport.

Astronomy, the body and face of the sun and moon, such as they appear to us on the earth; or the body and face of the earth, such as it appears to a spectator in the moon.

Optics, is the width of the aperture of telescope glasses, whatever their form be, whether plane, convex, concave, &c.