Dn – Dz


See Deoxyribonucleic acid.


Do Androids Dream of Electric Sheep?

Written by sci fi giant Philip K. Dick and published in 1968, this novel, which inspired the 1982 film Blade Runner, is the story of bounty hunter Rick Deckard, assigned to hunt down fugitive androids known as “replicants” in a world where all animals are extinct and replaced with man-made versions.


Dr. Evil

Born Douglas “Dougie” Powers but raised unaware of his birth family, Dr. Evil is the villain in the Bond-spoofing Austin Powers trilogy of films featuring Mike Meyers.  He is a graduate of the British Intelligence Academy and Evil Medical School.  Between 1967 and 1997, he spent his time cryogenically frozen inside a rocket shaped like a Big Boy statue.  He emerged to carry out his long-term goals of world domination and the acquisition of one million dollars.


Dr. Octopus

One of Spider-Man’s most dangerous archenemies, Dr. Octopus, also known as “Doc Ock,” was born Otto Octavius, and had a rather turbulent upbringing.  Determined not to become like his abusive father, Otto threw all his efforts into his education, regularly scoring top marks.  His father’s death in an industrial accident pushed Otto further towards the study of, and obsession with, physical science.  Otto was a brilliant and respected nuclear physicist, inventor and lecturer.  He became the youngest person to serve on the National Board of Nuclear Science.  He designed a set of highly advanced mechanical arms to assist him with his research into atomic physics.  The tentacled arms, resistant to radiation and capable of great strength and highly precise movement, were attached to a harness that fit around his body.  Later, he learned that either the radiation or his own internal low-level mutation had allowed his brain to control the movement of the arms.  The accident also affected his brain, either by damaging it or by causing his brain to adapt to his body’s four new extra limbs, and the scientist turned to a life of crime.  The tentacles have since been surgically removed from his body, although Octavius retains the power to control them telepathically from a great distance.

Once legally blind without the aid of his extremely thick eyeglasses, recent depictions of Doc Ock have shown him without lenses at all, presumably through laser surgery. With his harness attached, he is physically superior to Spider-Man; in his first appearance (in Marvel Comics‘ The Amazing Spider-Man #3, July 1963), he beat Spider-Man so badly that the wall-crawler considered giving up his heroic career

Over the years, Dr. Octopus has remained one of Spider-Man’s most dangerous foes.  His crowning achievement was the near-fatal stabbing of Spider-Man’s then-partner/lover, the Black Cat, who was placed in critical condition.  This led to Spider-Man beating Dr. Octopus within an inch of his life. The trauma of the beating he received from Spider-Man left Octavius severely phobic of Spider-Man and spiders in general for years.  Doctor Octopus has also worked with other supervillains on several occasions, most notably as the leader of the original incarnation of the Sinister Six.

Doctor Octopus was murdered by the insane Peter Parker clone named Kaine, but resurrected by a branch of the mystical ninja cult known as the Hand.  The villain has appeared in comics and animated series, and on the big screen, Dr. Octopus appeared in 2004’s Spider-Man 2, portrayed by Alfred Molina.


Doctor Who

Debuting on British television in 1963, Doctor Who features the exploits of a Time Lord from the planet Gallifrey.  Time Lords travel through space and time in what is known as a TARDIS, which is supposed to be able to change its appearance to suit its surroundings.  The Doctor’s, however, only appears as a blue British police box wherever he goes.  The Doctor has amassed many foes and many companions throughout his exploits.  Chief among his enemies are Daleks and The Master, another Time Lord.  Time Lords’ biology allows them to regenerate rather than die, a device used to explain how several actors of varying physical appearances have portrayed The Doctor over the decades.




Business consultant, management consultant, megalomaniac … as pets go, Dilbert’s dog is not what you would call typical.  He talks, he schemes, he scams, and he finds humans to be mere fodder for sarcasm and abuse.  Spouting such gems as “You’re not entitled to your opinion” and “Vote for me or the terrorists will use your skulls as a salad bowl,” the only thing he really has in common with other dogs is his inability to keep his tail from wagging when he is happy. (He seems to be happy only when he is scamming a human.)  This co-star of Scott AdamsDilbert comic strip, page-a-day calendars and 1999-2000 animated TV series is also the “author” of Dogbert’s Top Secret Management Handbook, Clues for the Clueless: Dogbert’s Big Book of Manners, and Build a Better Life by Stealing Office Supplies.



  1. A group of computers and devices on a network that are administered as a unit with common rules and procedures. Within the internet, domains are defined by the internet protocol (IP) address. All devices sharing a common part of the IP address are said to be in the same domain.
  2. In database technology, domain refers to the description of the values of one or more IP addresses.  For example, the domain name microsoft.com represents about a dozen IP addresses.  Domain names are used in web addresses to identify particular webpages.  For example, in the address http://nerdictionary.com/index.php/dn-dz/, the domain name is nerdictionary.com.  Every domain name has a suffix that indicates which top level domain (TLD) it belongs to.  There are only a limited number of such domains. For example:


gov – government agencies

edu – educational institutions

org – organizations (nonprofit)

mil – military

com – commercial business

net – network organizations

Domains can also be from other countries of origin:

ca – Canada

th – Thailand



Notorious among all comic book villains for having killed Superman, Doomsday debuted in DC Comics’ Superman: Man of Steel #18 in December 1992.  The Death of the Superman was a multi-part storyline published in alternating Superman titles, including Superman: The Man of Steel; Justice League of America; Superman (Volume 2); Adventures of Superman; and Action Comics, from December 1992 to January 1993.  (The single-issue story arcs were later compiled and resold in bound volumes: The Death of Superman; Superman: The Death and Return of Superman; and Superman: The Death and Return of Superman Omnibus.)

Created by Mike Carlin, Dan Jurgens, Roger Stern, Louise Simonson, Jerry Ordway and Karl Kesel, the story starts as a green-clad humanoid creature beats its way out of an underground chamber, and up to the surface.  Once above ground, it instantly starts to destroy every living thing it encounters.  As the creature continues its rampage, heroes from the Justice League International American are alerted, and answer the call to action.  Doomsday plows through Superman and the Justice League of America, and inevitably, the brawl boils down to a street fight between Superman and the creature.  During the battle, its protective garb is torn little by little to reveal a massive creature covered in sharp, jagged bone, which wounds Superman repeatedly, showing the reader the very rare sight of Superman bleeding.  After Superman and his love Lois Lane share a kiss, Superman lunges at the creature one last time, ending in the Man of Steel lying bloodied and still in the street.

After more than 150 appearances (as of 2015) in various DC comic issues, Doomsday was ultimately destroyed by Imperiex’s atomic-explosion capability.



See Disk Operating System.



A mythical winged reptilian monster, which is typically portrayed as fire-breathing.


Dragon Ball

A manga series that follows the adventures of Goku as he trains in martial arts and explores the world in search of seven mystical orbs known as the Dragon Balls, which, when gathered together, can summon a wish-granting dragon.  Along his journey, Goku makes several friends and battles a wide variety of villains, many of whom also seek the Dragon Balls for their own purposes.


Dragon’s Lair

Featuring movie-quality artwork by former Disney animator Don Bluth, the popular arcade game was originally produced by Cinematronics in 1983.  In it, the player assumes the role of Dirk the Daring, a heroic knight who searches through a haunted castle in an attempt to rescue the beautiful Princess Daphne from the evil Singe The Dragon.  To accomplish this, he must overcome all kinds of obstacles and villains, such as Lava Monsters, Giddy Goons, The Lizard King, The Grim Reaper, The Black Knight and ultimately, Singe himself.  The game featured a joystick to guide Dirk’s direction and a button to cause Dirk to swing his sword. Correct moves at the right times allowed Dirk to advance through the castle … but wrong decisions brought about immediate death, and the player was faced with Dirk’s aggravated expression, just before becoming a collapsing skeleton.  The game also became available in LaserDisc format, and spawned a sequel game, Dragon’s Lair II.



Set in a 6th Century kingdom called Urland, this 1981 fantasy adventure film tells of a classic quest, in which an apprentice wizard named Galen seeks to slay the dragon Vermithrax.


Dresden Files, The

Based on the popular Jim Butcher novel series, the 2007 one-season Sci-Fi Channel show centered around modern-day Chicago private eye Harry Dresden … who just so happens to be a bona fide wizard, as well!  When the local police are stumped by grisly, bizarre cases involving werewolves, vampires, or otherworldly forces, they go to Harry.  With the assistance of “Bob,” an ancient spirit who resides in a skull, Harry followed leads the cops couldn’t.  Executive produced by Nicolas Cage, the series starred Paul Blackthorne, Valerie Cruz and Terrence Mann.


Drive-by download

A type of internet virus or malicious software (or “malware”) by which dangerous code installs, and then infects, a computer or device, simply by visiting or opening a compromised page.  By doing so, the user unwittingly downloads a virus or malware onto the computer or mobile device.  The drive-by download usually takes advantage of (or “exploits”) a browser, app, or operating system that is out of date or has a security flaw.  The initial code is often very small and unnoticeable, since its job is often simply to contact another computer, from which the rest of the code can be downloaded onto your smartphone, tablet or computer.  Often, an infected webpage will contain different types of malicious code, in hopes that one of them will match a weakness on your computer.  Rather than being completely self-contained, the exploit code itself is hosted on a different web server and is exposed through the compromised web page using a technique like a URL embedded in malicious script code or an inline frame. Such downloads may be placed on otherwise innocent and normal-looking websites.  It might be a link in an email, text message, or social media post that tells you to look at something interesting on a site, with an attached link.  When you open the page, while you are enjoying an article, cartoon, or other link, the download is installing on your computer.

Additionally, malware distribution networks tend to be moving targets, with servers constantly appearing and disappearing in different locations.  As malware distribution servers get blocked by services such as search engines, they lose their effectiveness and attackers move them elsewhere.

Security researchers detect drive-by downloads by keeping track of web addresses that are known to have a history of malicious or suspicious behavior, and by using crawlers to wander the internet and visit different pages.  If a web page initiates a download on a test computer, the site is given a risky reputation.  Links in spam messages and other communications can also be used as source lists for these tests.


Drop-down menu

A horizontal list of choices on your computer screen that each contain a vertical menu of options, which is revealed, or “drops down,” when a user rolls over or clicks one of the primary options.  These drop-down options can be selected by clicking to select it.  Drop-down menus are typically created using DHTML (or dynamic HTML), which may include a combination of HTML, CSS, and JavaScript code.  They can also be written as flash drive applications.  While most software program menus typically require you to click on the main menu to reveal the drop-down options, most website drop-down menus often appear when you simply move the cursor over the main menu.  Also known as a pull-down menu.


Duke Nukem

A series of adult-rated video games, or the main character for which they are named.



An underground prison, typically within a castle.


Dungeon master

In the Wizards of the Coast game of Dungeons and Dragons, the player who runs the game, and thus rules over the dungeon.  Also known by the abbreviation “DM.”


Dungeons and Dragons

Originally designed by Gary Gygax and Dave Arneson, and first published in 1974 by the now-defunct Tactical Studies Rules, Inc. (TSR), Dungeons and Dragons (also known as D&D, DND, AD&D, ADND, etc.) is the abbreviation for a popular role-playing game (see RPG) owned by Wizards of the Coast (WOTC), a subsidiary of Hasbro.  D&D has had many iterations to its rule system through the years, and thus, may be referred to by the specific version being played, i.e., AD&D (Advanced Dungeons & Dragons, also known as 2nd Ed.). Each version has its pros and cons, with equally passionate supporters and detractors. “D&D” can also be used as a blanket term for all forms of tabletop role-playing systems, even if they aren’t actually using a D&D rule set.


Dunning-Kruger effect

First reported in an influential 1999 article in the Journal of Personality and Social Psychology, the “cognitive bias” described by Cornell University psychology professors Drs. David Dunning and Justin Kruger states that people with little knowledge or skill tend to compensate for their shortcomings by believing they have more talent than they actually do and by overlooking and/or underplaying the knowledge and talent of others.  Conversely, the most competent people often underestimate their abilities.  The study further suggested that incompetent people lack the skills necessary to distinguish good performers from bad performers.



See Digital video disc (DVD).


Dvorak keyboard layout


Conceived and patented in 1936 by Dr. August Dvorak and his brother-in-law Dr. William Dealey, the unique keyboard layout was designed to achieve more efficient typing than the standard QWERTY keyboard.  Dvorak first conceived of the keyboard design when he served as advisor to a student who was writing a Master’s thesis on typing errors.  Dvorak concluded that a more efficient layout needed to be devised to serve people with high words-per-minute rates.  Dvorak recognized a number of inherent flaws in the QWERTY layout: more than half of all keystrokes occurred on the top row, requiring typists to move their fingers off the home row keys; most key presses were performed by the left hand, which was typically nondominant; and about 30% of all typing was performed in the bottom row, which was the hardest to reach.

Considering this data, Dvorak and Dealey’s design featured: the most frequently used letters situated on the home row, so a typist’s fingers would not have to move in order to type them; all vowels were located on the left hand’s home row; and the more commonly used letters were situated on the top row, as moving the fingers up was easier than moving them down.

Dvorak began training typists on his keyboard and entering them in typing competitions.  His trainees won numerous typing awards, until contestants using QWERTY keyboards actually asked that the Dvorak boards be banned from competitions because the key configuration presented an “unfair advantage.”  Not long after Dvorak’s keyboard was released, the Tacoma, Washington school district began an experiment using the new layout.  Teachers trained 2,700 students on Dvorak keyboards and found the students were able to master the typewriter in one-third the time it took students to learn the QWERTY method.  However, after a new school board was elected, it was decided to terminate the Dvorak classes.  Despite this, there are some famous modern-day proponents of Dvorak’s design, including author Terry Goodkind, BitTorrent inventor Bram Cohen, and Apple co-founder Steve Wozniak.



See Digital video recorder (DVR).


Dynamic Duo

First used in Batman #4 in October 1940, this colloquial name for the DC Comics crime-fighting team of Batman and Robin was commonly used during the 1960s TV series Batman.


Dynamic internet protocol address (DIPA)

When computers and devices in a network are turned on for the first time, they are assigned an internet protocol (IP) address by a Dynamic Host Configuration Protocol (DHCP) server.  As opposed to a static IP address, which is permanent, a dynamic IP address is a temporary address that is assigned each time a computer or device accesses the internet.  Internet service providers (ISPs) typically assign dynamic addresses to the Internet connections of their residential and small business customers, which are less expensive than static addresses.



A universe or society in which oppressive control and the illusion of a perfect society are maintained through corporate, bureaucratic, technological, moral, or totalitarian governmental control.  Often characterized by elements of human misery, such as squalor, oppression, disease and/or overcrowding.  Dystopias, through an exaggerated worst-case scenario, can be and have been used to criticize a current trend, societal norm or political system.  The opposite of utopia (definition 1).



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