21-letter words containing a, l, t, m
- metropolitan district — any of the districts making up the metropolitan counties of England: since 1986 they have functioned as unitary authorities, forming the sole principal tier of local government. Each metropolitan district has an elected council responsible for education, social services, etc
- modulus of elasticity — the ratio of the stress applied to a body or substance to the resulting strain within the elastic limit
- monochloroacetic acid — chloroacetic acid.
- mother-of-pearl cloud — nacreous cloud.
- mother-of-pearl glass — an American art glassware having colored glass set into indentations in a thickness of opaque glass, the whole covered with clear glass and etched slightly with acid.
- motherwell and wishaw — a burgh in the Motherwell district, in S Scotland.
- motivational research — the application of the knowledge and techniques of the social sciences, especially psychology and sociology, to understanding consumer attitudes and behavior: used as a guide in advertising and marketing.
- multi-level marketing — Multi-level marketing is a marketing technique which involves people buying a product, then earning a commission by selling it to their friends. The abbreviation MLM is also used.
- multichannel analyser — an electronic instrument, such as a pulse height analyser, that splits an input waveform into a large number of channels in accordance with a particular parameter of the input
- multilayer perceptron — A network composed of more than one layer of neurons, with some or all of the outputs of each layer connected to one or more of the inputs of another layer. The first layer is called the input layer, the last one is the output layer, and in between there may be one or more hidden layers.
- multiplex transmitter — a transmitter that sends signals by multiplex
- multiplication factor — the ratio of the number of neutrons in a generation to the number of neutrons in the previous generation: when the multiplication factor is equal to or greater than one, a chain reaction is possible
- municipal corporation — a city, town, village, etc., that operates under a corporate charter granted by the state.
- muon-catalysed fusion — an experimental form of nuclear fusion in which hydrogen and deuterium muonic atoms are formed. Because the mass of the muon is much larger than that of the electron, the atoms are smaller, and the nuclei are close enough for fusion to occur
- myocardial infarction — heart attack. Abbreviation: MI.
- negotiable instrument — order or promise to pay money
- nightmare file system — Pejorative hackerism for Sun's Network File System (NFS). In any nontrivial network of Suns where there is a lot of NFS cross-mounting, when one Sun goes down, the others often freeze up. Some machine tries to access the down one, and (getting no response) repeats indefinitely. This causes it to appear dead to some messages (what is actually happening is that it is locked up in what should have been a brief excursion to a higher spl level). Then another machine tries to reach either the down machine or the pseudo-down machine, and itself becomes pseudo-down. The first machine to discover the down one is now trying both to access the down one and to respond to the pseudo-down one, so it is even harder to reach. This situation snowballs very quickly, and soon the entire network of machines is frozen - worst of all, the user can't even abort the file access that started the problem! Many of NFS's problems are excused by partisans as being an inevitable result of its statelessness, which is held to be a great feature (critics, of course, call it a great misfeature). ITS partisans are apt to cite this as proof of Unix's alleged bogosity; ITS had a working NFS-like shared file system with none of these problems in the early 1970s. See also broadcast storm.
- non-maintainer upload — (operating system) (NMU) A release of a Debian package by someone other than its usual maintainer. E.g. "The bug was fixed in a recent NMU."
- non-repeating decimal — a decimal representation of any irrational number, having the property that no sequence of digits is repeated ad infinitum.
- northumberland strait — the part of the Gulf of St. Lawrence that separates Prince Edward Island from New Brunswick and Nova Scotia, in SE Canada. About 200 miles (320 km) long; 9–30 miles (15–48 km) wide.
- oil-in-water emulsion — An oil-in-water emulsion is a mixture in which an oily medicine is dispersed in water or other liquid.
- olympic national park — a national park in NW Washington. 1323 sq. mi. (3425 sq. km).
- open telecom platform — (communications, library) (OTP) A set of standard, open source libraries and tools for use with Erlang.
- operational amplifier — a high-gain, high-input impedance amplifier, usually an integrated circuit, that can perform mathematical operations when suitably wired.
- operational semantics — (theory) A set of rules specifying how the state of an actual or hypothetical computer changes while executing a program. The overall state is typically divided into a number of components, e.g. stack, heap, registers etc. Each rule specifies certain preconditions on the contents of some components and their new contents after the application of the rule. It is similar in spirit to the notion of a Turing machine, in which actions are precisely described in a mathematical way. Compuare axiomatic semantics, denotational semantics.
- ophthalmia neonatorum — inflammation of the eyes of a newborn child due to an infectious disease, as gonorrhea, contracted during birth from the infected mother.
- pacific daylight time — the version of Pacific Standard Time that is in use when daylight saving time is being observed
- parliamentary inquiry — a question asked of the presiding officer of a parliament in relation to parliamentary law
- partial reinforcement — the process of randomly rewarding an organism for making a response on only some of the occasions it makes it
- payload assist module — a U.S. solid-propellant rocket used to boost a medium-weight spacecraft from a circular low-earth orbit to an elliptical transfer orbit for later insertion into a geosynchronous orbit. Abbreviation: PAM.
- peephole optimisation — (compiler) A kind of low-level code optimisation that considers only a few adjacent machine code instructions at a time and looks for certain combinations which can be replaced with more efficient sequences. E.g. ADD R0, #1 ADD R0, #1 (add one to register R0) could be replaced by ADD R0, #2 as long as there were no jumps to the second instruction.
- peephole optimization — peephole optimisation
- pentamethylenediamine — cadaverine.
- piezoelectric ceramic — any ceramic that exhibits piezoelectric properties.
- politically motivated — If an act of violence is politically motivated, it is carried out in the interests of a particular government or political party.
- portable commodore 64 — (computer) A version of the Commodore 64 modelled after the original Osborne portable PCs, with a flip-down keyboard that revealed a 5-inch colour monitor, and a built-in 1541 floppy disk drive. It is thought that few were made but that they did go on sale, at least in Canada.
- portable common loops — (PCL) A language which started out as an implementation of CommonLoops and turned into a portable CLOS implementation. Version 1992-08-28. It runs under Lucid Common LISP 4.0.1 and CMU Common LISP 16e.
- premature ejaculation — a male psychosexual disorder in which ejaculation occurs soon after the commencement of sexual intercourse.
- premenstrual syndrome — a complex of physical and emotional changes, including depression, irritability, appetite changes, bloating and water retention, breast soreness, and changes in muscular coordination, one or more of which may be experienced in the several days before the onset of menstrual flow. Abbreviation: PMS.
- prince rupert's metal — a brass composed of from about 60 to 85 percent copper and about 15 to 40 percent zinc, used to imitate gold.
- private member's bill — In Britain, a Private Member's Bill is a law that is proposed by a Member of Parliament acting as an individual rather than as a member of his or her political party.
- programmed cell death — a normal, genetically regulated process leading to the death of cells and triggered by the presence or absence of certain stimuli, as DNA damage.
- propantheline bromide — a substance, C 2 3 H 3 0 BrNO 3 , used in the treatment of peptic ulcers.
- public address system — loudspeaker
- public administration — the implementation of public policy, largely by the executive branch.
- public-address system — a combination of electronic devices that makes sound audible via loudspeakers to many people, as in an auditorium or out of doors.
- pulmonary circulation — the circulation of blood from the heart to the lungs for oxygenation and back to the heart.
- pulse code modulation — a form of modulation that transforms a wave-form, as an audio signal, into a binary signal in which information is conveyed by a coded order of pulses for transmission, storage on a disk, or processing by a computer. Abbreviation: PCM.
- pulse-code modulation — a form of modulation that transforms a wave-form, as an audio signal, into a binary signal in which information is conveyed by a coded order of pulses for transmission, storage on a disk, or processing by a computer. Abbreviation: PCM.
- pulse-time modulation — radio transmission in which the carrier is modulated to produce a series of pulses timed to transmit the amplitude and pitch of a signal. Abbr.: PTM.