sagitta

The keystone of an arch.

Geometry, Mathematics, Sciences The distance from a point in a curve to the chord; also, the versed sine of an arc; so called from its resemblance to an arrow resting on the bow and string.

Biology, Natural sciences, Zoology, Zootomy The larger of the two otoliths, or earbones, found in most fishes.

Any arrowworm, of the genus Sagitta.