Tensile strength – the ratio of maximum load to original cross-sectional area. Also called ultimate strength.

Thermography -- the use of infrared thermography whereby temperatures of a wide variety of targets can be measured remotely and without contact. This is accomplished by measuring the infrared energy radiating from the surface of the target and converting this measurement to an equivalent surface temperature.

Thermal conductivity -- measure of the ability of a solid or liquid to transfer heat.

Thermal stability -- ability of a fuel or lubricant to resist oxidation under high temperature operating conditions.

Thin film lubrication -- a condition of lubrication in which the film thickness of the lubricant is such that the friction between the surfaces is determined by the properties of the surfaces as well as by the viscosity of the lubricant.

Thixotropy -- tendency of grease or other material to soften of flow when subjected to a shearing stress, followed by a return to original consistency when the stress is removed.

Traceability – the ability to trace a reported measurement through an unbroken chain of comparisons to a national or international standard.

Tribology -- the science and technology of interacting surfaces in relative motion, including the study of lubrication, friction and wear. Tribological wear is wear that occurs as a result of relative motion at the surface.

Turbidity -- the degree of opacity of a fluid.

Turbulent flow sampler -- a sampler that contains a flow path in which turbulence is induced in the main stream by abruptly changing the direction of the fluid.