| Virion | (Environmental Engineering) A virus particle. Viral DNA or RNA enclosed in an organic capsule. See virus. |
| 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. |
| Waste minimization | (Environmental Engineering) The elimination or reduction of a waste prior to its generation. This is accomplished by process changes rather than waste treatment methods. |
| Weak acid | (Environmental Engineering) An acid that does not ionize completely under the conditions of interest. Examples include acetic acid, carbonic acid, and hypochlorous acid. See strong acid. |
| 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) - |
| Adaptive maintenance - | (Software Engineering) activity associate with changing an application to make it conform to changes in its external environment |
| Aesthetic design - | (Software Engineering) a Web engineering action that focuses on the aesthetics (e.g., the artistic elements) of a WebApp (often encompasses graphic design) |
| Agile development (also referred to as agile process model) - | (Software Engineering) an adapted version of software engineering that emphasizes customer communication, incremental software delivery, informal methods and work products, and highly motivated teams. |
| Architecture - | (Software Engineering) the overall structure of software components, the data and/or content that components manipulate, and the relationships between them |