| Sterilization | (Environmental Engineering) The destruction or inactivation of all microorganisms. See Disinfection. |
| Thiols | (Environmental Engineering) Organic compounds which contain the "-SH" functional group. Also called mercaptans. |
| Troposphere | (Environmental Engineering) The lower atmosphere, from the earth's surface to approximately 12 km. This portion of the earth's atmosphere contains about 95 percent of the atmospheric gases. The temperature gradually declines through this region. |
| Ultimate disposal | (Environmental Engineering) The process of returning residuals back to the environment in a form which will have the minimal or reduced negative environmental impacts. |
| Virus | (Environmental Engineering) A submicroscopic genetic constituent which can alternate between two distinct phases. As a virus particle, or virion, it is DNA or RNA enveloped in an organic capsule. As an intracellular virus, it is viral DNA or RNA inserted into the host organisms DNA or RNA. |
| Wetland | (Environmental Engineering) Semi-aquatic land, that is land that is either inundated or saturated by water for varying periods of time during each year, and that supports aquatic vegetation which is specifically adapted for saturated soil conditions. |
| Abstraction - | (Software Engineering) (1) the level of technical detail of some representation of software; (2) a cohesive model of data or an algorithmic procedureAction (also called Software engineering action) - |
| Architecture - | (Software Engineering) the overall structure of software components, the data and/or content that components manipulate, and the relationships between them |
| Aspect-oriented development - | (Software Engineering) a development approach that emphasizes "concerns" (also called "aspectual requirements" that incorporate features, functions and information content) that cut across multiple system functions |
| Change control - | (Software Engineering) an umbrella process that enables a project team to accept, evaluate, and act on changes in a systematic manner |