1D, 1-D, or 1d can refer to: *

Alpha-1D adrenergic receptor The alpha-1D adrenergic receptor (α1D adrenoreceptor), also known as ADRA1D, is an alpha-1 adrenergic receptor, and also denotes the human gene encoding it. Receptor There are 3 alpha-1 adrenergic receptor subtypes: alpha-1A, -1B and -1D, all of ...

Astra 1D Astra 1D is a geostationary communications satellite launched in 1994 by the Société Européenne des Satellites ( SES). , the craft remains in service for occasional use. Astra 1D was the fourth, and under original plans, last Astra communic ...

, a satellite *

Canon EOS-1D The Canon EOS-1D is a professional digital single-lens reflex camera launched in November 2001 as part of Canon's flagship EOS-1 series. It was the first digital camera in the EOS-1 line, succeeding Canon's final flagship film camera, the 1V. It ...

, 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 ...

, 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 th ...

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 gro ...

, 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