The following technical terms lists important technical items concerning non-contact temperature measurement.

Absolute zero -273,18°C. There is no molecular action at this temperature and body's do not have thermal energy.
Ambient temperature compensation Possibility of correction by a device to gain higher accuracy in that case the ambient temperature of the device is different to the foreground temperature (reflected energy) of the measured object.
Air purge unit Accessory to keep the optics free of dust and other dirt
Opening of the shutter of an objective
Aperture unit Opening of aperture of a lens
Black body Perfect radiation source which absorbs the whole impinge radiation energy for all wavelength. For a real black body emissivity is 1 at all wavelength.
Calibration certificate Official calibration expertise by an calibration agency
Calibration To measure accurately in comparison with international temperature scale
Calibration radiation source Realising of a black body to calibrate pyrometers
°C (Celsius) Temperature scale based on fix point 0° (zero degree) as freezing point of water and 100° as evaporation point of water at normal pressure °C = (°F-32) / 1,8
Data memory To save measured data, allows to read out or analyse measuring values
Detector Radiation receiver transforming heat radiation into an electrical signal.
Emissivity The emissivity is the ratio of reflected infrared energy of an object at a certain temperature in a certain spectral range compared to the radiation energy of a real black body with same temperature and spectral range.For a real black body emissivity is 1 at all wavelength.
Emissivity ratio Ratio of emissivity of two different spectral bands of a ratio pyrometer. Emissivity of the short wavelength will be divided by the wavelength of the longer wavelength. The emissivity ratio can be bigger, equal or smaller than 1. The emissivity ratio is going to be important in that case the emissivity changes with the wavelength.
Focal point or focal distance Point or distance of the pyrometer at which the object is focussed to the detector of the pyrometer and the optical resolution at its biggest.
Fixed optic Optic with fixed focal width without focus setting
Fibre optics pyrometer Pyrometer with separated optical head which is connected via its fibre optics cable to the measuring transformer
Grey body Body whose emissivity <1 is considered constant at all wavelengths
Intensity Radiation performance
Inspection certificate Certificate about measurement uncertainty of a device
Laser pointer Accessory for exactly adjustment by using a laser as light source
Lens Optical system consisting of one or more lenses or mirrors, displaying the measured object at the detector of the pyrometer
Maximum value storage Accessory, saving the biggest measured temperature in a given and adjustable time frame
Measuring distance Distance in-between measured object and lens leading edge of the pyrometer
Measuring object Object temperature is going to be measured.
Optics pyrometer System to define temperature of a source by comparison with a standard light source (usually with help of human eyes).
Over-all radiation pyrometer Pyrometer which is nearly sensitive to heat radiation in the whole spectral range.
Pyrometer Instrument to measure temperatures without making contact with the object to be measured (radiation thermometer)
Ratio pyrometer Pyrometer using signals from two close to each other spectral ranges and ratio formation to find out the temperature
Reproducibility Uncertainty to repeat a measurement value at same condition
RS 232 Standardised serial interface for digital communication
RS 485 Standardised serial interface for digital communication (bus interface) that allows higher number of receivers and senders at one wire
Scanning optics Equipment to re-direct the pyrometer radiation setting to a line vertical to the optic axis, so that the surface of the object can be scanned. The scanner moves the spot sizes across the object.
Spectral range Area of spectral range which is used by the pyrometer when taking readings
Spot size Area on the object from which the pyrometer receives most (90%) of the signals
Storage temperature Ambient temperature to store and use the pyrometer correctly.
Through lens sighting Optical accessory for accurate pyrometer adjustment
Transmission The passing of radiation through a solid, liquid or gas;the transmission coefficient gives the ratio between intensity of radiation that has passed through, to the incoming radiation.
Wavelength describes the length of a wave between two points in a single phase