DD

DD, dd, or other variants may refer to:

• DD in hexadecimal = 221
• DD, a brassiere measurement

Companies

• d.d., Croatian term for a public limited liability company; dioničko društvo (literal: joint stock company)
• DD National or DD1, an Indian national channel
• DuPont's stock ticker symbol

Computing

• .dd, a hypothetical domain name for the German Democratic Republic
• dd, an HTML element for specifying definition data
• dd (Unix), a program that copies and convert files and data
• Deckadance, a DJ program for Windows and Mac OS X designed by Image-Line
• Deployment descriptor, a component in Java Platform, Enterprise Edition applications
• Logo for Dolby Digital, audio compression technologies developed by Dolby Laboratories
• Double density, a capacity designation on magnetic storage, usually floppy disks

Entertainment

• Daredevil, a Marvel Comics character
• DD, a character in The Saga of Seven Suns novels by Kevin J. Anderson.

Military

• DD tank, an amphibious tank
• Dishonorable discharge, a punitive discharge in the US Military
• DD, the US Navy hull classification for destroyers

Science and technology

• Data Deficient, a rating on the IUCN Red List of Threatened Species
• Decimal degrees, geographic coordinates shown using decimal fractions

Transportation

• D-D locomotive, the AAR classification for a railway locomotive with two four-axle bogies
• Nok Air's IATA code
• DD, the licence plate code for Dresden, Germany

Other uses

• Dd (digraph), a digraph in the Welsh language
• Degree of Difficulty, a diving score modifier
• Doctor of Divinity or D.D.
• Direct deposit, used in banking
• Drug and Disease, used in Personals ads as "D&D Free"