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Damages: The sum of money awarded to the injured party in a personal injury lawsuit.

Damped Frequency: The frequency of oscillation of an under-damped second order filter.

Damping Ratio: Control parameter for a second order filter. 

Data Source Object: Software that receives data from a physical device, translates the data into standard units, maintains equipment status, and provides a common interface for each variation of a particular device. 

Data Transfer System: A device for transferring data which includes avionics; it is similar to a diskette drive. 

Dead Reckoning: A method of navigation based on basic information (barometric altitude, magnetic heading, airspeed, wind conditions) from best available source; sometimes short for air data dead reckoning. 

Default Judgment: A judgment issued when the defendant offers no defense by not responding to the complaint. A judge may issue a judgment without the necessity of a trial.

Defendant: The person against whom a claim is brought.

Denied-Boarding Compensation: Payment given passengers who have been bumped from a flight, cruise, or land-tour. Compensation may be in the form of a free trip, money, or accommodations. 

Deponent: The person who testifies at a deposition.

Deposition: A pretrial discovery device in which one party verbally answers questions from the other party.

Derivative: Rate of change, usually with respect to time.

Derived: Calculated values for which no direct measurement exists.

Desired Path: A trajectory in space determined by guidance to meet the current mission objectives. 

Desired Speed: A guidance control law parameter generated by the longitudinal guidance modes.

Deviation: A different plan or path from what was initially desired. 

Device: A piece of equipment or a subsystem; synonyms with physical device, unit. 

Difference Equation: A mathematical relationship to model a discrete function, expressed in terms of other values in the sequence. Difference equations are usually derived from differential equations. 

Differential Equation: A mathematical relationship to model a continuous function, expressed in terms of derivatives. Initial conditions are usually given or implied. In avionics, differential equations are commonly used by systems engineers to model avionics systems. The systems engineer usually converts differential equations to difference equations for specification and implementation in software. In avionics, a differential equation usually models continuous-time phenomenon in terms of time derivatives.

Digital Map Generator: Digital equipment that produces map video, and sometimes contains TRN; uses Digital Terrain Elevation Data and Digitized Feature Analysis Data; displays reconstructed digital map data, aeronautical charts and/or photographs. The digital map data can be annotated with natural and man-made features as well as threats. 

Direct Flight: Any flight between two places that carries a single flight number. Unlike a nonstop, a direct flight will make one or more stops between two places. The passenger may have to change planes or even change airlines. This is a change in meaning. In the past, direct flights made stops but required no change of plane. 

Discovery: Methods and procedures by which information is made available to each party prior to trial. Discovery may include depositions, interrogations, requests for production of documents, and demands for independent medical examinations.

Discrete Time: Time divided into quantized intervals; in avionics, time is usually divided into equal intervals to create a periodic process.

Discrete-Time Equation: A mathematical relationship to describe a function of time, expressed in terms of discrete time.

Distance Measuring Equipment: Equipment for measuring distance, usually from an aircraft to a ground station; usually part of a Tactical Air Navigation System. 

Docket: A summary system kept by the clerk’s office which contains a record of all pleadings, court orders and other important activities in a case.

Domestic Airline: An air carrier that provides service within its own country. Also called a domestic carrier.

Doppler Navigation System: A navigation for measuring velocity by radiating and determining frequency shift. 

Doppler: A technique for measuring velocity by radiating and determining frequency shift.

DPLR: Doppler navigation system.