Initialism of double data rate.
"The computer's performance improved significantly after upgrading to DDR memory, which is an initialism for double data rate technology."
In plain English: DDR is the type of computer memory that lets your laptop and phone store data quickly so they run smoothly without lagging.
"The computer store had several different types of RAM, including DDR and older models in stock."
East Germany (from German DDR, initialism of Deutsche Demokratische Republik)
"When I was a child, my grandmother often told me stories about growing up in the DDR."