19-letter words containing a, d, r, o
- data encryption key — (DEK) Used for the encryption of message text and for the computation of message integrity checks (signatures). See cryptography.
- data protection act — (legal) (DPA) A UK law guaranteeing rights to individuals in relation to personal data that others hold on them. For example, under the DPA, you have the right to see what data a company holds on you.
- datatron 200 series — (computer) A family of computers produced by Burroughs that included the Datatron 204 and Datatron 220.
- davy jones's locker — the bottom of the sea; grave of those drowned at sea or buried there
- de broglie equation — the postulate of wave mechanics that a particle of mass m moving at a velocity v will have the properties of a wave of wavelength h / mv (de Broglie wavelength) where h is Planck's constant.
- de-compartmentalize — to divide into categories or compartments.
- de-internationalize — to make international, as in scope or character: a local conflict that was internationalized into a major war.
- de-militarised zone — (networking) (DMZ) (From the military term for an area between two opponents where fighting is prevented) DMZ Ethernets connect networks and computers controlled by different bodies. They may be external or internal. External DMZ Ethernets link regional networks with routers to internal networks. Internal DMZ Ethernets link local nodes with routers to the regional networks. Compare red zone.
- declaration of love — a statement made by one person to another in which they say they are in love with the other person
- deflate compression — deflate
- deflationary spiral — Geometry. a plane curve generated by a point moving around a fixed point while constantly receding from or approaching it.
- deindustrialisation — Alternative spelling of deindustrialization.
- deindustrialization — the decline in importance of manufacturing industry in the economy of a nation or area
- demonstration model — a nearly new product, such as a car or washing machine, that has been used only to demonstrate its performance by a dealer and is offered for sale at a discount
- dendrochronological — Pertaining to dendrochronology.
- dental receptionist — a receptionist working in a dental surgery
- department of labor — the department of the U.S. federal government that promotes and improves the welfare, opportunities, and working conditions of wage earners. Abbreviation: DOL.
- department of state — the department of the U.S. federal government that sets forth and maintains the foreign policy of the U.S., especially in negotiations with foreign governments and international organizations. Abbreviation: DOS.
- departmentalisation — Alternative spelling of departmentalization.
- departmentalization — to divide into departments.
- dependable software — software reliability
- desargues's theorem — the theorem that if two triangles are so related that the lines joining corresponding vertices meet in a point, then the extended corresponding lines of the two triangles meet in three points, all on the same line.
- developable surface — a surface that can be flattened onto a plane without stretching or compressing any part of it, as a circular cone.
- devil's coach-horse — a large black rove beetle, Ocypus olens, with large jaws and ferocious habits
- devils-on-horseback — a savoury of prunes wrapped in bacon slices and served on toast
- diamond anniversary — a 60th, or occasionally 75th, anniversary
- diamond ring effect — a phenomenon, sometimes observed immediately before and after a total eclipse of the sun, in which one of Baily's beads is much brighter than the others, resembling a diamond ring around the moon.
- diamond-leaf laurel — a tree, Pittosporum rhombifolium, of Australia, having coarsely toothed, oval or diamond-shaped leaves and white flowers, widely planted as an ornamental in the southwestern U.S.
- dictionary of names — a dictionary of given names that indicates whether a name is usually male, female, or unisex and often includes origins as well as meanings; for example, as by indicating that Evangeline, meaning “good news,” comes from Greek. Used primarily as an aid in selecting a name for a baby, dictionaries of names may also include lists of famous people who have shared a name and information about its current popularity ranking.
- dielectric constant — Electricity. the ratio of the flux density produced by an electric field in a given dielectric to the flux density produced by that field in a vacuum.
- difference equation — (mathematics) A relation between consecutive elements of a sequence. The first difference is D u(n) = u(n+1) - u(n) where u(n) is the nth element of sequence u. The second difference is u(n+2) + a u(n+1) + b u(n) = 0 can be converted to a difference equation (in this case, a second order linear difference equation): D2 u(n) + p D u(n) + q u(n) = 0 and vice versa. a, b, p, q are constants.
- diffraction grating — a band of equidistant, parallel lines, usually more than 5000 per inch (2000 per centimeter), ruled on a glass or polished metal surface for diffracting light to produce optical spectra.
- diffraction pattern — the phenomenon exhibited by wave fronts that, passing the edge of an opaque body, are modulated, thereby causing a redistribution of energy within the front: it is detectable in light waves by the presence of a pattern of closely spaced dark and light bands (diffraction pattern) at the edge of a shadow.
- dig one's own grave — If you say that someone is digging their own grave, you are warning them that they are doing something foolish or dangerous that will cause their own failure.
- digital electronics — (electronics) The implementation of two-valued logic using electronic logic gates such as and gates, or gates and flip-flops. In such circuits the logical values true and false are represented by two different voltages, e.g. 0V for false and +5V for true. Similarly, numbers are normally represented in binary using two different voltages to represented zero and one. Digital electronics contrasts with analogue electronics which represents continuously varying quantities like sound pressure using continuously varying voltages. Digital electronics is the foundation of modern computers and digital communications. Massively complex digital logic circuits with millions of gates can now be built onto a single integrated circuit such as a microprocessor and these circuits can perform millions of operations per second.
- digital photography — the taking or manipulation of photographs that are stored as data files on a computer.
- dimethylnitrosamine — a yellow, water-soluble carcinogenic liquid, C 2 H 6 N 2 O, found in tobacco smoke and certain foods: known to be a potent carcinogen. Abbreviation: DMN, DMNA.
- direct grant school — (in Britain, formerly) a school financed by endowment, fees, and a state grant conditional upon admittance of a percentage of nonpaying pupils nominated by the local education authority
- direction indicator — aerial used in wireless communication
- directional coupler — (communications) (tap) A passive device used in cable systems to divide and combine radio frequency signals. A directional coupler has at least three ports: line in, line out, and the tap. The signal passes between line in and line out ports with loss referred to as the insertion loss. A small portion of the signal power applied to the line in port passes to the tap port. A signal applied to the tap port is passed to the line in port less the tap attenuation value. The tap signals are isolated from the line out port to prevent reflections. A signal applied to the line out port passes to the line in port and is isolated from the tap port. Some devices provide more than one tap output line (multi-taps).
- disciplinary action — punishment or caution
- discretionary trust — a trust in which the beneficiaries' shares are not fixed in the trust deed but are left to the discretion of other persons, often the trustees
- discriminated union — (theory) The discriminated union of two sets A and B is A + B = {(inA, a) | a in A} U {(inB, b)| b in B} where inA and inB are arbitrary tags which specify which summand an element originates from. A type (especially an algebraic data type) might be described as a discriminated union if it is a sum type whose objects consist of a tag to say which part of the union they belong to and a value of the corresponding type.
- dispersion relation — the relationship between the angular frequency (ω;) of a wave and the magnitude of its wave vector (k). Thus the wave's speed is ω/k
- displaced homemaker — a woman recently divorced, separated, or widowed after many years as a homemaker.
- ditty bag (or box) — a small bag (or box) used as by sailors for holding sewing equipment, toilet articles, etc.
- diversional therapy — the structured use of leisure time in recreation and play as a form of or supplement to conventional therapy
- dollard-des-ormeaux — a town in S Quebec, in E Canada: suburb of Montreal.
- domain architecture — (systems analysis) A generic, organisational structure or design for software systems in a domain. The domain architecture contains the designs that are intended to satisfy requirements specified in the domain model. A domain architecture can be adapted to create designs for software systems within a domain and also provides a framework for configuring assets within individual software systems.
- dominance hierarchy — a system or set of relationships in animal groups that is based on a hierarchical ranking, usually established and maintained by behavior in aggressive encounters: one or a few members hold the highest rank and the others are submissive to those ranking higher and dominant to those ranking lower.