The trace of a matrix is the sum of the terms along the principal diagonal.
Ornament of ribs, bars, etc., in panels or screens, as in the upper part of a Gothic window.
Track Radar
Radar that provides continuous range, bearing, and elevation data by keeping the RF beam on the target.
Tracking Filter
A low-pass or band-pass filter which automatically tracks the input signal.
Traction Battery
A battery designed to be used to provide the power to move a vehicle.
Traction Control
A means of electronically reducing the power to the driving wheels, to minimise wheel-spin, and maximise traction.
Tractor Propeller
Propeller mounted forward of the engine.
A metal rod having pointed ends, used to mark off a span equal to its length.
A transmission and differential combined in one integrated assembly.
A device that both transmits and receives data.
Not algebraic.
The ratio of the current at the output port and the voltage at the input ports.
A device that receives energy in one form and supplies an ouput in another form.
Transfer Control Protocol
A common protocol which a computer can use to communicate with other computers.
Transfer Function
In a linear elastic structure, the displacement at one point caused by the application of a dynamic force at another point depends on the transfer function between the two points.
Transfer Orbit
An elliptical trajectory tangent to the orbits of both the departure planet and the target planet.
Transfer Pump
A pump employed to move a fluid from one location to another.
Transfer RNA
A form of RNA that binds to amino acids.
Transfer Switch
A switch or switches arranged to permit transferring a conductor connection from one circuit to another without interrupting the current.
Transfinite Cardinals
Defined as collections (equivalency classes) of sets that could be put into a 1-1 correspondence with each other.
A transform is a mathematical operation that converts a function from one domain to another domain with no loss of information.
A change in the size, shape, location or orientation of a figure.
Transformation Rate
The reciprocal of the time necessary for a reaction to proceed halfway to its completion.
Transformation Temperature Ranges
Those ranges of temperature within which austenite forms during heating and transforms during cooling.
A transformer is a device used for converting an alternating electric current from one voltage to another.
Transformer Core
The centre part of a transformer around which wire is wound.
Transformer Efficiency
The ratio of output power to input power, generally expressed as a percentage.
Transformer Oil
A highly-refined mineral oil that is stable at high temperatures and has excellent electrical insulating properties.
Through or across crystals or grains.
Transgranular Fracture
Fracture of polycrystalline materials by crack propagation through the grains.
Transient Analysis
Analysis of the transient vibration which is generated in response to an input which is only applied for a short duration.
Transient Inrush Current
The current that results when a switching device is closed to energize a capacitive or inductive circuit.
Transient Overvoltage
The voltage which occurs during the transient conditions resulting from the operation of a switching device.
Transient Response
The ability of a system to respond quickly and accurately to transients.
A three leaded device (Collector, Base, Emitter) used for amplifying or switching.
Transistor-Transistor Logic (TTL)
Referring to logic circuits consisting of two or more directly interconnected transistors, to provide conditional switching capability.
Transition Fit
A fit between a hole and a shaft where both clearance and interference may occur in the coupling.
Transition Metal
An element with an incomplete d subshell.
Transition Point
The point of change from laminar to turbulent flow.
Transition Temperature
An arbitrarily defined temperature that lies within the temperature range where metal fracture characteristics change rapidly.
Transitional Low Emission Vehicle
A vehicle that is certified to meet the TLEV emission standards established by the California Air Resources Board.
Describes the property that if the relation holds between a first object and a second, and between the second and a third, then it holds between the first and the third.
In a tessellation, to translate an object means repeating it by sliding it over a certain distance in a certain direction.
Movement in a straight line without rotation.
Translation Energy
The energy associated with random straight line motion of gas molecules.
Motion through space as opposed to rotation.
Translational Control
The regulation of the rate of a protein′s synthesis by regulation of the rate of translocation of the ribosome.
Translational Repressor
A repressor that blocks translation of a mRNA.
Those substances, such as frosted glass, through which some light rays can pass but through which objects cannot be seen clearly.
The nondimensional ratio of the response amplitude of a system in steady-state forced vibration to the excitation amplitude.
Propagation or the passing of something through or onwards.
Transmission Electron Microscope
A microscope that produces an image by using electron beams to pass through the specimen, making examination of internal features at high magnifications possible.
Transmission Error
This is the difference between the actual position of the output gear and the position it would occupy if the gear drive were perfect.
Transmission Line
A structure that guides electromagnetic energy.
Transmit Receive Tube
A gas-filled Radio Frequency switch that is used as a duplexer.
Equipment that generates and amplifies an Radio Frequency carrier, modulates the Radio Frequency carrier with intelligence, and radiates the signal into space.
Transmitter Frequency
The frequency of an unmodulated transmitter output.
Transmitting Antenna
The device used to send the transmitted signal energy into space.
A process of converting one element to another by irradiating or bombarding it with radioactive particles.
Speeds slightly above and below the speed of sound.
Those substances, such as glass, that pass almost all of the light waves falling upon them.
Passage of water from the roots of a plant to the atmosphere via the vascular system and the stomata of the leaves.
A miniature receiver-transmitter that can be tracked by a radio-direction finder.
Lists all Transport topics in the Encyclopaedia
Transport Weblinks
Lists all Transport Weblinks in the Encyclopaedia
Proteins that span a membrane and transport specific molecules across the membrane.
The movement of a gene or set of genes from one site in the genome to another.
A segment of DNA that can move from one position in the genome to another.
A chemical term referring to artificially manufactured elements which have an atomic number higher than uranium.
A line that intersects 2 others.
Transverse Electric Mode
A waveguide mode in which the entire electric field is perpendicular to the wide dimension and the magnetic field is parallel to the length.
Transverse Electromagnetic Mode
The radial distribution of intensity across a beam as it exits the optical cavity.
Transverse Engine
An engine layout in a vehicle where the crankshaft axis lays across the vehicle.
Transverse Magnetic Mode
A waveguide mode in which the entire magnetic field is perpendicular to the wide dimension and some portion of the electric field is parallel to the length.
Transverse Ray Error
Errors, or departures from ideal, measured in a direction perpendicular to the optical axis.
Transverse Wave
A wave in which the vibrations of the medium are perpendicular to the direction the wave is moving.
A network in which all arcs can be traced without going over one more than once.
A quadrilateral in which no sides are parallel.
A quadrilateral that has at least one pair of parallel sides.
Travelling Wave Tube
Electron tube in which a beam of electrons interacts continuously with the electric field of an electromagnetic wave traveling in a helix to produce amplification at ultra-high frequencies and above.
One movement across the surface of the work being machined.
The higher frequencies of the audible spectrum.
Tree Diagram
A schematic way of showing the number of ways a compound event may occur.
Tree Topology
LAN topology similar to linear bus topology, except that tree networks can contain branches with multiple nodes.
Trellis-Code Modulation
Combined coding and modulation technique.
Tremendously High Frequency
The band of frequencies from 300 gigahertz to 3,000 gigahertz.
Trevithick, Richard
British inventor and mining engineer. His most significant success was the high pressure steam engine and he was also the builder of the first full-scale working railway steam locomotive.
Similar to a thyristor but allows current to flow in both directions.


Long chain Alkane that is a solid at room temperature.

A unit of quantity equal to three.
A three sided shape.
Triangular Number
A number of the form n(n+1)/2.
In general, the unique location of the source from some combination of at least three ranges and/or bearings in three dimensional space.
The geological period from 245 million to 208 million years ago.
A special type of monopole antenna array.
The technology of interacting surfaces in relative motion and concerned with the design, friction, lubrication, and wear of contacting surfaces that move relative to one another.
Tricarboxylic Cycle
Another name for the Krebs Cycle.


A solvent and dry cleaning fluid.

Another name for Trichlorethene.


A colourless, nearly odorless liquid that boils at about room temperature. This was the first widely used refrigerant.

Alternative name for Gallium III Chloride.
Alternative name for Gallium III Chloride.
Another name for Chloroform.
Alternative name for Antimony Trichloride.
Trickle Charge
A charge at a low rate.
Having three axes of any length with none of the included angles being equal to one another or 90 degrees.
Tricuspid Valve
The flaps between the right atrium and the right ventricle.
A 13 sided polygon.
Alternative name for Antimony Trifluoride.
A short pulse, either positive or negative, that can be used to cause an electronic function to take place.
An ester of glycerol and three fatty acids.
A three-sided polygon - a triangle.
Trigonal Bipyramidal
A molecular shape that results when there are five bonds and no lone pairs on the central atom in the molecule.
Trigonal Planar
A molecular shape that results when there are three bonds and no lone pairs around the central atom in the molecule.
Trigonal Pyramidal
A molecular shape that results when there are three bonds and one lone pair on the central atom in the molecule.
The basic Sum and Difference equations along with other trigonometric functions.
Trigonometric Functions
These are functions of an angle. They relate the angles of a triangle to the lengths of its sides.
Lists all Trigonometry topics in the Encyclopaedia
Trigonometry Books
Lists all Trigonometry Books in the Encyclopaedia
Trigonometry Calculations
Lists all Trigonometry Calculations in the Encyclopaedia
Trigonometry Conversions
Lists all Trigonometry Conversions in the Encyclopaedia
Trigonometry Weblinks
Lists all Trigonometry Weblinks in the Encyclopaedia
Method of surveying wherein the lengths of the triangle sides are measured.
Trade name for Trichlorethene.
Trilithium Nitride
Old name for Lithium I Nitride.
A number equal to 1012.
Trimmer Capacitor
A small variable capacitor used in parallel across a larger capacitor to adjust the total capacitance a small amount.
Used as a high explosive and known as TNT.

An algebraic expression consisting of 3 terms.
An electronic amplifying valve with three main electrodes.
A simple sugar with a backbone containing three carbon atoms.
A compound with three atoms of oxygen with an element or radical.
Trip Element
The part of a circuit breaker that senses any overload condition and causes the circuit breaker to open the circuit.
Trip Free Circuit Breaker
A circuit breaker that will open a circuit even if the operating mechanism is held in the ON position.
Trip-Free Relay
An auxiliary relay whose function is to open the closing circuit of an electrically operated switching device so that the opening operation can prevail over the closing operation.
A fixed wing aeroplane with 3 wings arranged one above the other.
A group of three items.
Triple Bond
A covalent bond that involves 3 bonding pairs.
Triple Point
The temperature at which solid, liquid and vapour can exist together in equilibrium.
Tripod Mounts
The thread on tripod mounts is 1/4"-20 UNC, which is the smaller more common size. For larger cameras the 3/8"-16 UNC thread is used.
To cut an object into three equal parts.
A radioisotope of hydrogen with two neutrons and one proton in its nucleus.
Nucleus of a tritium atom.
Trivalent Impurity
Acceptor impurities containing only three valence electrons.
Abbreviation of Transfer RNA.
Malware that appears to perform a desirable function for the user but instead facilitates unauthorized access to the user's computer system.
Trojan Points
The two dynamically stable Lagrange points.
Trojan Satellites
Satellites which orbit a body at one or the other Trojan points relative to a secondary body.
A three-square polyomino.
Tropical Year
1 tropical year = 31.55693x106 seconds
The movement of a plant in response to a stimulus.
The cold region in t earth′s atmosphere located about 10 km above the surface.
The portion of the atmosphere, closest to the surface of the earth, where all weather phenomena take place.
Tropospheric Ducting
The propagation of radio signals above 30 Mhz via bending and ducting along weather fronts in the lowest layer of the Earth′s atmosphere.
Tropospheric Scatter
The propagation of radio waves in the troposphere by means of scatter.
Tropospheric Wave
A radio wave that is propagated by reflection from a place of abrupt change in the dielectric constant or its gradient in the troposphere.
Trouble Tables
Tables of trouble symptoms and probable causes, furnished by many manufacturers to help technicians isolate problems.
The process of locating and diagnosing faults in equipment by means of systematic checking or analysis.
A valley of a wave disturbance.
A handtool with a flat sheet steel surface that is rectangular or pointed and is used to manipulate and finish concrete or plaster.
Troy Ounce
An old British unit of mass mainly used for measuring prescious metals. 1 troy ounce = 31.1035 g
True Altitude
Actual height above sea level; calibrated altitude corrected for air temperature.
True Bearing
Angle between a target and true north measured clockwise in the horizontal plane.
True Density
The mass of a particle divided by its volume, excluding open pores and closed pores.
True Electrode Area
The surface area of an electrode taking into consideration the surface roughness.
True Meridian
A great circle through the geographical poles.
True North
Geographic north.
True Power
The power dissipated in the resistance of the circuit, or the power actually used in the circuit.
True Strain
The ratio of the change in dimension, resulting from a given load, to the magnitude of the dimension immediately prior to applying the load.
True Stress
The load applied to a material divided by the cross sectional area over which it acts.
True Sun
The actual sun as it appears in the sky.
True Volume
Volume excluding open and closed pores.
The closeness of an average measurement to a "true" value, while accuracy is the the closeness of a single measurement to the true value.
To eliminate without round-off some low-order bits, often after performing an arithmetic computation.
Truncated Paraboloid
A paraboloid reflector that has been cut away at the top and bottom.
Truncated Pyramid
A section of a pyramid between its base and a plane parallel to the base.
Truncation Error
Error resulting from the use of only a finite number of terms of an infinite series or from the approximation of operations.
Truncation Ratio
The dimensionless ratio of the Gaussian beam diameter at the 1/e2 intensity point to the limiting aperture of the lens.
Trunnion Bearing
A bearing used as a pivot to swivel or turn an assembly.
Structural framework of triangular units for supporting loads over long spans.
Truth Table
A tabular representation of a logic gate showing all the possible combinations.
Try Square
A joinery tool for testing timber or lumber for square, that is 90 Degrees.