Engineering Dictionary

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An alphabetical listing of General terms and items.

M   Dico Tools
Mega; one million. When referring to memory capacity, two to the twentieth power (1,048,576 in decimal notation).

Machicolated   Dico Tools
Provided with machicolations.

Machicolated Battlements   Dico Tools
Battlements provided with machicolations.

Machicolated Corner Gallery   Dico Tools
A wall gallery situated at the corner of a fortification; usually provided with arrow slits, which added to the defensive capacity of the wall.

Machicolated Gallery   Dico Tools
A gallery provided with machicolations, situated at the top of a curtain wall or just below the level of the wall walk, dating from the 14th century.

Machicolated Gatehouse   Dico Tools
A gatehouse provided with machicolations. See gatehouse.

Machicolated Turret   Dico Tools
A turret which was built out on consoles, the holes between the consoles were used as machicolations. Also known as a bartizan or machicoulis. See flanking turret.

Machicolated Wall Walk   Dico Tools
See machicolated battlements.

Machicolation   Dico Tools
A series of openings provided by

Machicoulis   Dico Tools
(1) A single or a small number of machicolations, which was positioned over a gate, doorway or some other vulnerable angle of the defences. Developed as a substitute for the hourd as did the machicolation but served to provide particular defence of a position, an example is the box machicolation. See box machicolation. (2) Machicoulis were also used built around the angles of towers and curtain walls, often semi-circular in shape, known as bartizans, which were used to defend the area below as well as flanking the neighbouring positions. See bartizan, flanking turret. (3) A square aperture in the floor of the room above an entry, which was used to attack the enemy from above, usually covered by a trap door, and was known as a murder hole. (4) Machicoulis has also been used to refer to machicolation is some texts.

Machine Language   Dico Tools
Instructions that are written in binary form that a computer can execute directly. Also called object code and object language.

Magistral Line   Dico Tools
The main line of defence or the crest of the scarp of a fortification. In drawings of fortifications it is usually drawn in a thicker line than the other lines.

Main Guard   Dico Tools
The strongest building of a fortification, usually the keep.

Main Work, Major Work   Dico Tools
The chief work of a fortification, as opposed to the outworks.

Malvoisin   Dico Tools
(1) A type of siege tower. (2) An earthwork fort or mound designed to be used to blockade the approaches to a fortification under siege.

Mandrel (Balancing Arbor)   Dico Tools
An accurately machined shaft on which work is mounted for balancing.

Manor House   Dico Tools
See fortified manor.

Mantlet Wall   Dico Tools
The outer wall of a late medieval castle that was situated between the main curtain and the moat. (L. mantellum, cloak).

Manual Reset (Adjustment)   Dico Tools
The adjustment on a proportioning controller which shifts the proportioning band in relationship to the set point to eliminate droop or offset errors.

Manual Reset (Switch)   Dico Tools
The switch in a limit controller that manually resets the controller after the limit has been exceeded.

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Manzil   Dico Tools
A fortified hostel on the Iberian peninsula.

Marsad (Rutba)   Dico Tools
Small isolated fortification along the main roads for military traffic of Andalusia.

Masonry   Dico Tools
a building material such as stone, clay, brick, or concrete

Mass Flow Rate   Dico Tools
Volumetric flowrate times density, i.e. pounds per hour or kilograms per minute.

Mass Storage   Dico Tools
A device like a disk or magtape that can store large amounts of data readily accessible to the central processing unit.

Mastio   Dico Tools
An Italian term meaning donjon or keep.

Masugata Mon   Dico Tools
The barbican gatehouse used to defend the main access route of a Japanese castle, positioned at either the crossings of the inner, middle, or outer moats, or at the main entrance to the castle. The barbican gatehouse consisted of a walled square or rectangular courtyard provided with two gateways

Maximum Elongation   Dico Tools
The strain value where a deviation of more than 5% occurs with respect to the mean characteristic (diagram of resistance change vs strain).

Maximum Excitation   Dico Tools
The maximum value of excitation voltage or current that can be applied to the transducer at room conditions without causing damage or performance degradation beyond specified tolerances.

Maximum Flanking Effect   Dico Tools
The much sought after ideal amount of flanking effect, which increases a fortifications defencibility.

Maximum Operating Temperature   Dico Tools
The maximum temperature at which an instrument or sensor can be safely operated.

Maximum Power Rating   Dico Tools
The maximum power in watts that a device can safely handle.

Mean Ionic Activity Coefficient (f) Or The Activi   Dico Tools
f = (f+n+f-n-)1/n

Mean Temperature   Dico Tools
The average of the maximum and minimum temperature of a processequilibrium.

Measurand   Dico Tools
A physical quantity, property, or condition which is measured.

Measuring Junction   Dico Tools
The thermocouple junction referred to as the hot junction that is used to measure an unknown temperature.

Mechanical Engineer   Dico Tools
An engineer who applies the principles of mechanics and energy to the design of machines and devices

Mechanical Hysteresis   Dico Tools
The difference of the indication with increasing and decreasing strain loading, at identical strain values of the specimen.

Medium Effect (f M)   Dico Tools
For solvents other than water the medium effect is the activity coefficient related to the standard state in water at zero concentration. It reflects differences in the electrostatic and chemical interactions of the ions with the molecules of various solvents. Solvation is the most significant interaction.

Melting Point   Dico Tools
The temperature at which a substance transforms from a solid phase to a liquid phase.

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Membrane   Dico Tools
The pH-sensitive glass bulb is the membrane across which the potential difference due to the formation of double layers with ion-exchange properties on the two swollen glass surfaces is developed. The membrane makes contact with and separates the internal element and filling solution from the sample solution.

Merlon   Dico Tools
(1) The portion of a battlemented parapet that rises up from a wall (eg. the solid part of a parapet between the crenels). (2) The part of a parapet between two embrasures. See battlement, crenel, embrasure, guelph merlon, half merlon, irish battlement, parapet, stepped merlon, venetian battlement. (I. merlone, battlement).

Merlon Arrow Slit   Dico Tools
An arrow slit which was situated in the centre of a merlon, the addition of the arrow slit added to the potential fire power of the wall head defences. They also provided better protection to the archers than firing through the crenels. See arrow slit, merlon.

Method Of Correction   Dico Tools
A procedure whereby the mass distribution of a rotor is adjusted to reduce unbalance, or vibration due to unbalance, to an acceptable value. Corrections are usually made by adding material to, or removing it from, the rotor.

Meurtrieres   Dico Tools
(1) Small loops through which the enemy could be attacked, usually situated in the gatehouse. Also known as murder holes and spy holes. See drop box, fall trap. (2) Small gun loops through which muskets could be fired at the enemy. See musket port.

Mica   Dico Tools
A transparent mineral used as window material in high-temperature ovens.

Microamp   Dico Tools
One millionth of an ampere, 10-6 amps, A.

Microcomputer   Dico Tools
A computer which is physically small. It can fit on top of or under a desk; based on LSI circuitry, computers of this type are now available with much of the power currently associated with minicomputer systems.

Micron   Dico Tools
One millionth of a meter, 10-6 meters.

Microvolt   Dico Tools
One millionth of a volt, 10-6 volts.

Middle Bailey   Dico Tools
A bailey which was situated between the outer and the inner bailey's of a castle. See bailey, concentric castle.

Mil   Dico Tools
One thousandth of an inch (.001").

Mile Castle   Dico Tools
A Roman fort which was used to defend a part of a fortified perimeter (eg. Hadrian's Wall) situated every Roman mile along the length of the perimeter, (approximately every 1.5 kilometres). A mile castle was constructed on a rectangular plan covering 300 to 400 square metres, provided with a barrack-room, a store, an oven and a latrine. There were two gates; the inner leading to civilized lands while the outer was provided with turrets, and opened to the barbarian lands. Also known as a castellum.

Milliamp   Dico Tools
One thousandth of an amp, 10-3 amps, symbol mA.

Millimeter   Dico Tools
One thousandth of a meter, symbol mm.

Millivolt   Dico Tools
Unit of electromotive force. It is the difference in potential required to make a current of 1 millampere flow through a resistance of 1 ohm; one thousandth of a volt, symbol mV.

Mine   Dico Tools
(1) The works excavated by the besiegers to attack a fortifications defences by making a breach. The early method was to fill the excavated cavity under a wall with combustibles, set it a light, once the upright timbers burnt through the chamber collapsed bringing down the wall above, thus making a breach. The later method of using a mine to make a breach involved using gun powder, the gun powder was exploded in the excavated chamber under the walls, the resulting effects producing a breach. (2) Mines were made by besiegers while countermines were made by the besieged. See ecoutes.

Mineral-insulated Thermocouple   Dico Tools
A type of thermocouple cable which has an outer metal sheath and mineral (magnesium oxide) insulation inside separating a pair of thermocouple wires from themselves and from the outer sheath. This cable is usually drawn down to compact the mineral insulation and is available in diameters from .375 to .010 inches. It is ideally suited for high-temperature and severe-duty applications.

Minor Scale Division   Dico Tools
On an analog scale, the smallest indicated division of units on the scale.

Minor Work   Dico Tools
A lesser work which was used to defend a position or a major work. See outwork, main work.

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Mizuki   Dico Tools
A Japanese fortification consisting of a large earthen enbankment which was used as a dam to create a water defence against an attacking force. (J. water fort).

Moat   Dico Tools
A water filled ditch which surrounded a castle, or just forming a line of defence, which was artificial or partly natural in origin. Just as donjonsignified the highest part of a motte and bailey castle and was later changed to dungeon, so moat was derived from motte or the mound to the ditch from which it was excavated. In some cases the word moat is used to refer to a dry ditch. (Fr. motte, mound).

Moat Pier   Dico Tools
A pier of rock set amid a moat or ditch which was used to support a wooden bridge or drawbridge. Common in the Middle East because of the lack of strong enough timber to span the whole moat. Some piers were left standing when the moat was hewn out of the solid rock. Also known as drawbridge pier.

Moated   Dico Tools
Provided with a moat.

Mock Machicolation   Dico Tools
See blind machicolation, bracket, false machicolation.

Modem   Dico Tools
Modulator/Demodulator. A device that transforms digital signals into audio tones for transmission over telephone lines, and does the reverse for reception.

Moineau, Moyeneau   Dico Tools
A small flat bastion, usually situated in the middle of a overlong curtain, from which musketeers defended the neighbouring bastions with small shot flanking fire, otherwise the bastions would be inadequately defended due to their distance apart. (Fr. moineau, sparrow).

Molality   Dico Tools
A measure of concentration expressed in mols per kilogram of solvent.

Mon   Dico Tools
A gateway of a Japanese castle, which was of two main types; the gateway which was constructed of timber similar in style to a tenshu, and the other gateway was simpler and made into the stone walls or the ishigaki of a castle. 

Monolithic Dome   Dico Tools
A dome composed of a series of arches, joined together with a series of horizontal rings called parallels

Monovalent Ion   Dico Tools
An ion with a single positive or negative charge (H+, C1-).

Moon   Dico Tools
An outwork constructed in the form of a crescent. See demilune, ravelin.

Moorish Merlon   Dico Tools
A merlon which was typical of the fortified  architecture, characterized by a pointed apex.

Mote, Motte   Dico Tools
A natural, partly natural or artificial earthen mound surmounted by a wooden donjon surrounded by a palisade, and in turn surrounded by palisaded bailey or the bailey was placed to one side; the motte was usually surrounded by a ditch which was also surrounded the palisaded bailey. The motte and bailey were connected by a flying bridge. The motte and bailey castle was common in France and wasintroduced to England by the Normans, who used them to consolidate their territorial gains. See kernmotte.

Motherboard   Dico Tools
The pc board of a computer that contains the bus lines and edge connectors to accommodate other boards in the system. In a microcomputer, the motherboard contains the microprocessor and connectors for expansion boards.

Motte & Bailey Castle   Dico Tools
See bailey, motte.

Mounting Error   Dico Tools
The error resultant from installing the transducer, both electrical and mechanical.

Movable Bridge   Dico Tools
A bridge in which the deck moves to clear a navigation channel; a swing bridge has a deck that rotates around a center point; a drawbridge has a deck that can be raised and lowered; a bascule bridge deck is raised with counterweights like a drawbridge; and the deck of a lift bridge is raised vertically like a massive elevator

MSD (Most-Significant Digit)   Dico Tools
The leftmost digit of the display.

Mudejar Merlon   Dico Tools
A merlon which was built with a pointed apex, typical of mudejar fortified architecture. See moorish merlon, pointed merlon.

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Mueller Bridge   Dico Tools
A high-accuracy bridge configuration used to measure three-wire RTDthermometers.

Multiple Lines   Dico Tools
A number lines of detached walls which were used to defend a position. See concentric castle, lines of defence (1).

Multiplex   Dico Tools
A technique which allows different input (or output) signals to use the same lines at different times, controlled by an external signal. Multiplexing is used to save on wiring and I/O ports.

Multivallate Hillfort   Dico Tools
A hillfort which was surrounded by a number of ditches and ramparts, which were either built originally as a multivallate hillfort or had a number of ditches and ramparts added, thus a univallate or a bivallate hillfort could develop into a multivallate hillfort. This development in hillfort design was made necessary by the importation of the sling to Britain, the sling which had a longer range compared to that of the throwing spear. This made it necessary to keep the enemy further away from the principle defences, this was achieved by extending the outworks. This however, does not suggest that all univallate hillforts pre-date all multivallate hillforts. See hillforts.

Mural Gallery   Dico Tools
A gallery constructed within the thickness of the wall below the parapet, which was provided with arrow slits. See firing gallery.

Mural Tower   Dico Tools
A tower attached to the curtain wall which was used for flanking the curtain wall. See bastion, curtain tower, wall tower. (L. murus, wall).

Murder Hole   Dico Tools
(1) An opening in the floor of the room of a gatehouse situated above the entry passage or in other important places, which was used to attack the enemy below. See drop box, (2) The gaps of the machicolations which were used to attack the enemy at the base of a castles walls. See machicolation, murderess.

Murderes   Dico Tools
The square gun ports which were used in coastal artillery forts of the late 15th and early 16th century England.

Murderess   Dico Tools
The gap of a machicolation, which was used to attack the enemy at the base of the wall below. See machicolation, murder hole.

Musket Port   Dico Tools
A port which was designed for the use of muskets, dating from the 16th century. Also called musket embrasures. See gun port.

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