|folding rule: see rule.
|folding rule and level: a compound instrument combining the functions of both a folding rule and level.
|gauging rod: measuring stick, usually with a scale to provide a direct reading of volume, such as the liquid content of a barrel, or the weight of a cannonball.
|geographical astrolabe: form of astrolabe, where the lower plate is projected for the earth, while the rete includes the ecliptic.
|geographical planisphere: map of the earth, produced by geometrical projection of a sphere on to a flat surface. Included as the more prominent part of the geographical astrolabe.
|geometrical square: form of quadrant, with sides divided equally and having an alidade at one corner, used for measuring angles in terms of ratios in the manner of a shadow square on the back of an astrolabe.
|globe dial: form of sundial, where the hour lines are on the outer surface of a sphere.
|gnomon: the part of a sundial that casts the shadow for indicating the time.
|golden numbers: numbers denoting the positions of years in the lunar cycle, see article on time and date.
|graphometer: type of surveying instrument, see article on the graphometer.
|gunner's caliper: a instrument used to take dimensions in gunnery, such as the diameter of cannons and projectiles.
|gunner's compendium: an instrument combining several functions required by the gunner, often incorporating the gunner's sight and gunner's level, along with additional elements.
|gunner's folding rule: a folding rule carrying tables or scales specially adapted for the use of gunners.
|gunner's gauge scales: scales which provide the weight of a sphere (the shot) from a measurement of its diameter; in gunnery these scales were traditionally provided for iron, lead and stone.
|gunner's level: instrument used to set the elevation of a large gun, see article on the gunner's sight and level.
|gunner's rule: see rule.
|gunner's sight: instrument used to elevate and aim a large gun, see article on the gunner's sight and level.
|gunner's sight and level: instrument used to set a large gun to the horizontal, or to elevate and aim it on a target, see article on the gunner's sight and level.
|gunnery instrument: see gunner's compendium.
|hodometer: device for measuring distance by means of a wheel, pushed along the ground, attached to a geared movement with a dial or other form of distance register.
|horary quadrant: quadrant used to tell the time, usually from a measure of solar altitude, see article on the quadrant.
|horizon obliquus: line denoting the local horizon on an astrolabe latitude plate, see article on the astrolabe.
|horizon rectus: east-west line on an astrolabe latitude plate, see article on the astrolabe.
|horizontal dial: sundial where the hour lines are marked on a horizontal surface, see article on the sundial.
|hour lines: the time divisions on a sundial or other astronomical instrument.
|hour ring: the part of a sundial marked with the time divisions, where this part is in the form of a ring or broken ring.
|inclining dial: type of sundial projected as a horizontal dial for a particular latitude, but which can be inclined for use in a range of other latitudes.
|Italian hours: system of hour reckoning, see article on time and date.
|Jacob's staff: name for a cross-staff, especially when used for surveying, see article on the cross-staff.
|Julian calendar: calendar introduced by Julius Caesar and used in Europe until the sixteenth century, or later, see article on time and date.
|latitude: angle above or below the equator to indicate position on the earth. The celestial latitude, however, is an angular distance with respect to the ecliptic.
|latitude plate: part of an astrolabe with a projection of altitude and azimuth lines on to the equatorial plane, see article on the astrolabe.
|latitude projections: projection of altitude and azimuth lines on to the equatorial plane, see article on the astrolabe.
|level: name for different types of instrument used in surveying for determining the horizontal direction and differences in height, and in gunnery and elsewhere for adjusting something to the horizontal. See also gunner's level.
|level and sight: instrument used to set a large gun to the horizontal, or to elevate and aim it on a target, see article on the gunner's sight and level.
|limb: the outermost part or edge of a circular or part-circular instrument carrying a scale, usually divided in degrees.
|longitude: angle parallel to the equator to indicate position on the earth. The celestial longitude, however, is an angular distance parallel to the ecliptic.
|lunar dial: dial where the shadow is cast by moonlight instead of sunlight, see article on the sundial.
|lunar volvelle: volvelle indicating the age of the moon, which typically converts between the time indicated by the shadow of the moon on a sundial and solar time.
|magic square: square grid with a number in each cell for which the sum of each row, column and diagonal is the same.
|magnetic compass: instrument indicating directions by a magnetic needle, see article on the compass.
|magnetic deviation: the angle between geographical north and the direction indicated by a compass needle.
|magnitudes: numbers in a scale of the relative brightnesses of the stars, 1 being the brightest.
|mariner's astrolabe: altitude-measuring instrument for finding latitude at sea, having a heavy brass or bronze ring, suspended by a shackle and ring, with a degree scale and a centrally-pivoted alidade.
|mater: part of an astrolabe, see article on the astrolabe.
|mathematical compendium: compound instrument for performing various functions in practical mathematics.