See Also: Thermal(medicine)
thermal(dictionary)
thermal 2, noun(dictionary)
thermal sensors(medicine)
thermal spectrum(medicine)
thermal velocity(medicine)
sympto-thermal(dictionary)
thermal (as used in expressions)(encyclopedia)
thermal conduction(encyclopedia)
thermal energy(encyclopedia)

thermal (iou)



thermal adjective & noun. M18.
[French, from Greek therme heat + -AL1; in sense 1 partly formed as THERM noun1.]
A. adjective.
Of, pertaining to, or of the nature of hot springs; (of a spring etc.) naturally hot or warm; having hot springs. M18.
gen. Of or pertaining to heat; determined, measured, caused, or operated by heat. M19.
b. Of underwear etc.: promoting the retention of heat. L20.
Special collocations: thermal agitation = thermal motion below. thermal analysis Chemistry analysis of a substance by examination of the way its temperature falls on cooling or rises on heating. thermal barrier Aeronautics = heat barrier s.v. HEAT noun. thermal bremsstrahlung electromagnetic radiation produced by the thermal motion of charged particles in a plasma. thermal capacity the capacity of a body to store heat, measured by the quantity of heat required to raise its temperature one degree. thermal conductivity the rate at which heat passes through a substance, expressed as the amount of heat that flows per unit time through unit area with a temperature gradient of one degree per unit distance. thermal cycle a cycle in which the temperature of a substance rises or falls and then returns to its initial value. thermal death point the lowest temperature at which a micro-organism can be killed by heat exposure under specified conditions. thermal diffusion diffusion occurring as a result of the thermal motion of atoms or molecules, esp. as a technique for separating gaseous compounds of different isotopes of an element (which diffuse at different rates in a temperature gradient). thermal diffusivity the thermal conductivity of a substance divided by the product of its density and its specific heat capacity. thermal efficiency the efficiency of an engine measured by the ratio of the work done by it to the heat supplied to it. thermal equilibrium a state in which no net gain, loss, or transfer of heat occurs. thermal imaging the technique of using the heat given off by objects or substances to produce an image of them or to locate them. thermal inertia resistance to change of temperature. thermal lance = THERMIC lance. thermal motion motion of atoms or other particles due to their thermal energy. thermal neutron a neutron which is in thermal equilibrium with its environment (in contrast to a slow neutron). thermal noise Electronics electrical fluctuations arising from the random thermal motion of electrons. thermal paper heat-sensitive paper used in thermal printers. thermal pollution the production of heat, or the discharge of warm water, esp. into a river or lake, on a scale that is potentially harmful ecologically. thermal printer a printer having a matrix of fine pins as the printhead, which are selectively heated to form a character on heat-sensitive paper. thermal radiation: emitted (esp. as infrared radiation) from the surface of a body and dependent on its temperature. thermal reactor a nuclear reactor in which the fission process relies upon thermal neutrons. thermal resistance resistance to the leakage of heat energy, esp. from an electrical conductor. thermal runaway Electronics a dramatic or destructive rise in the temperature of a transistor as a result of an increase in its temperature causing an increase in the current through it, and vice versa. thermal shock a sudden large application of heat energy. thermal speed the speed characteristic of a thermal neutron. thermal storage a system of storing water at high pressure and temperature in vessels above the boilers during off-peak hours in electricity generating stations; also used attrib. to designate appliances which store heat in other ways. thermal unit a unit of heat; British thermal unit: see BRITISH adjective. thermal velocity = thermal speed above.
b. noun.
A rising current of relatively warm air, used by gliders and birds to gain height. M20.
In pl. Thermal underwear. L20.
thermalling, thermaling noun soaring in thermals or warm rising air currents; the production of thermals: M20.
thermally adverb in a thermal manner; by means of heat; as regards heat: L19.