The Noon Gun has been an historic time signal in Cape Town, South Africa since 1806. The gun is situated on Signal Hill, close to the centre of the city.

The settlement at the Cape of Good Hope was founded by the Dutch in 1652 and the signal guns were originally part of the regular artillery at the Imhoff Battery at the Castle in Cape Town. In 1795 during the Napoleonic Wars, Britain took the Cape Colony from the Dutch East India Company ((De) Vereenigde Oostindische Compagnie (VOC) in Dutch). The VOC transferred its territories and claims to the Batavian Republic in 1798 and ceased to exist in 1799. The British handed the Cape Colony back to the Batavian Republic in 1803. However, in 1806 the Cape was occupied again by the British after the Battle of Blaauwberg. Thereafter the British controlled the Cape continuously until it became a part of the independent Union of South Africa in 1910. Shortly after the English took over, the two Dutch guns were removed from the Imoff Battery and placed in town as signal guns. The Castle received the latest English 18 pounders. Because the very loud report of the cannons upset people nearby, the guns were eventually moved from the environs of the city itself to the somewhat more remote Lion Battery on Signal Hill at 33°54′54.6″S 18°24′41.85″E / 33.915167°S 18.411625°E / -33.915167; 18.411625 (Lion Battery)Coordinates: 33°54′54.6″S 18°24′41.85″E / 33.915167°S 18.411625°E / -33.915167; 18.411625 (Lion Battery). The first signal fired from there was on 4 August 1902.

Noon (also midday or noon time) is usually defined as 12 o'clock in the daytime. However the term midday is used colloquially to refer to a range of time, usually 11-1. The word noon is also used informally to mean midday regarding the location of the sun, as opposed to the middle of one's day. Although this is a time around the middle of the day when people in many countries take a lunch break. Solar noon is 12 o'clock apparent solar time, or around 12 – 1 p.m. local time depending on daylight saving time, the moment when the sun crosses the meridian and is about at its highest elevation in the sky. The clock time of solar noon depends on the longitude and date.

The opposite of noon is midnight.

In many cultures in the northern hemisphere, noon had ancient geographic associations with the direction "south" (as did midnight with "north" in some cultures). Remnants of the noon = south association are preserved in the words for noon in French (midi) and Italian (mezzogiorno), both of which also refer to the southern parts of the respective countries. Modern Polish and Ukrainian go a step farther, with the words for noon (południe, полудень – literally "half-day") also meaning "south" and the words for "midnight" (północ, північ – literally "half-night", as with English mid(dle) meaning "half") also meaning "north".

A gun is a muzzle or breech-loaded projectile-firing weapon. There are various definitions depending on the nation and branch of service. A "gun" may be distinguished from other firearms in being a crew-served weapon such as a howitzer or mortar, as opposed to a small arm like a rifle or pistol, but there are exceptions, such as the U.S. Air Force's GUU5/P. At one time, land-based artillery tubes were called cannon and sea-based naval cannon were called guns. The term "gun" evolved into a generic term for any tube-launched projectile-firing weapon used by sailors, including boarding parties and marines.

In modern parlance, a gun is a projectile weapon using a hollow, tubular barrel with a closed end — the breech — as the means of directing the projectile (as well as other purposes, for example stabilizing the projectile's trajectory, aiming, as an expansion chamber for propellant, etc.), and firing in a generally flat trajectory.

The term "gun" has also taken on a more generic meaning, by which it has come to refer to any one of a number of trigger-initiated, hand-held, and hand-directed implements, especially with an extending bore, which thereby resemble the class of weapon in either form or concept. Examples of this usage include staple gun, nail gun, glue gun, grease gun. Occasionally, this tendency is ironically reversed, such as the case of the American M3 submachine gun which carries the nickname "Grease Gun".