Sagitta

Origin

From Latin sagitta ("arrow").

Full definition of sagitta

Noun

1. The keystone of an arch.
2. (geometry) 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.
3. (anatomy) The larger of the two otoliths, or ear bones, found in most fishes.