• Da (play), a Tony-winning play by Hugh Leonard
• Da (film), a movie adaptation of the play by Hugh Leonard
• Dalton (unit), the atomic mass unit
• Adi Da, a spiritual leader once known as Da Free John, and Da Love-Ananda
• Da River in Vietnam
• SJ Da, a Swedish locomotive
• Deca-, an SI prefix for a factor of 10
• Da!, a Russian youth movement

DA or D.A. is an acronym or abbreviation for:

• DA postal area
• Daniel Amos, the American Rock band
• Danish language (ISO 639-1 alpha-2, da)
• Dark Ages (computer game)
• Darmstadt, a town in middle Germany
• Debtors Anonymous
• Deerfield Academy, a preparatory boarding school located in Deerfield, Massachusetts.
• Delt Ansvarlig Selskap, or DA, a Norwegian company form
• Democratic Alliance (South Africa), a South African political party.
• Department of Agriculture, an executive department in the Philippines.
• Deutsche Alternative (German Alternative), a rightist group
• DeviantArt, an online artistic community
• Diploma in Anaesthetics, an obsolete postgraduate qualification in anaesthetic practice
• DirectAdmin, a graphical web-based management utility
• District attorney (D.A.), a United States Attorney or County attorney
• The D.A. (1971 TV series), an NBC dramatic series
• The D.A. (2004 TV series), an ABC dramatic series
• Doctor of Arts degree
• Dopamine transmitter
• Doomsday argument
• Double anal A sexual act
• Dumbledore's Army in Harry Potter and the Order of the Phoenix
• Degtyarev Aviation-mounted, a Soviet machine gun
• Dura-Ace, a Shimano racing bicycle groupset
• Double action, a type of gun trigger
• Durham Academy, a private school
• Selskap med delt ansvar, a type of Norwegian company without limited liability
• Duck's Ass, a 1950's hairstyle