1D, 1-D, or 1d can refer to: * Alpha-1D adrenergic receptor * Astra 1D, a satellite * Canon EOS-1D, Canon's first professional digital camera *

Long March 1D The Long March 1D was a member of China's Long March rocket family. During the 1990s CALT developed an improved version of the DF-4 to test the reentry vehicle warheads of the DF-31. They took advantage of this development and offered it as the L ...

, a satellite *

One-dimensional space In physics and mathematics, a sequence of ''n'' numbers can specify a location in ''n''-dimensional space. When , the set of all such locations is called a one-dimensional space. An example of a one-dimensional space is the number line, where t ...

in physics and mathematics *

One Direction One Direction, often shortened to 1D, are an English-Irish pop boy band formed in London in 2010. The group are composed of Niall Horan, Liam Payne, Harry Styles, Louis Tomlinson, and previously Zayn Malik until his departure from the g ...

, an English-Irish boy band *

Penny (British pre-decimal coin) The British pre-decimal penny was a denomination of sterling coinage worth of one pound or of one shilling. Its symbol was ''d'', from the Roman denarius. It was a continuation of the earlier English penny, and in Scotland it had the same m ...

, routinely abbreviated ''1d.'' * 1D, the hexadecimal code for the Group Separator control character

See also