"Dialed Number Recorder". Referenced frequently in HBO's "The Wire", when the cops are talking about getting phone wiretaps on their targets. It records the phone calls that are intercepted.
Means "Do Not Rececitate"; slang used when drinking to acknowledge that you are going to drink a heavy load of alcohol and if you stop breathing do not want to be saved; used to speak of others who you wish if on the verge of death would not be revived.
DNR, often called a scratch, in track, refers to instances where an individual withdraws from the race before it begins. Not the same as DQ (or disqualification), in which a runner is removed after the start. Occasionally, in hand-timed races where there are less timers than runners, DNR will be used to indicate that a runner did not finish fast enough to have his/her time recorded.