|vertical dial: sundial where the hour lines are marked on a vertical surface, see article on the sundial.
|vertical disc dial: sundial where the hour lines are marked on a vertical surface in the form of a disc, see article on the sundial.
|volvelle: a device which rotates; usually referring to one or more discs which turn within a circular scale.
|wedge: the part of an astrolabe which secures the pin; also called the 'horse'.
|wegweiser: a circle marked with the points of the compass and a rotating index.
|wind names: a nomenclature for dividing an azimuth circle into degrees, where eight 45-degree scales are allocated to eight traditional named winds of the Mediterranean.
|wind rose: type of compass rose, where the directions are indicated by the names or initials of the traditional winds of the Mediterranean. May also refer to a whole instrument serving only to indicate the names of the wind directions.
|wind vane: flag-like vane mounted on a vertical post free to align itself with, and indicate the direction of, the wind. Also an instrument performing the same function.
|zenith: the point on the celestial sphere directly above the observer.
|zodiac: a band of 12 constellations of stars straddling the ecliptic; the ecliptic and zodiac are conventionally divided into these constellations, 30 degrees being allocated to each.