1D

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, a satellite
• One-dimensional space in physics and mathematics
• One Direction, an English-Irish boy band
• Penny (British pre-decimal coin), routinely abbreviated 1d
• <code>1D</code>, the hexadecimal code for the Group Separator control character
• Informal for Onedrive, a file hosting system operated by Microsoft

See also

• D1 (disambiguation)
• ID (disambiguation)
• LD (disambiguation)