Definition: A small constellation north of Aquila; the Arrow.
Definition: The keystone of an arch.
Definition: 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.
Definition: The larger of the two otoliths, or ear bones, found in
most fishes.
Definition: A genus of transparent, free-swimming marine worms having
lateral and caudal fins, and capable of swimming rapidly. It is the
type of the class Chaetognatha.
