| Softening | (Environmental Engineering) The removal of divalent cations by precipitation or ion exchange. |
| Sterilization | (Environmental Engineering) The destruction or inactivation of all microorganisms. See Disinfection. |
| Suspended growth reactor | (Environmental Engineering) A reactor in which the microorganisms are suspended in the wastewater. Examples of suspended growth reactors are activated sludge reactors and anaerobic digesters. See attached growth reactor. |
| 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. |
| 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. |
| Boundary value analysis - | (Software Engineering) a black box testing method that designs test cases that exercise data boundaries |
| Change control - | (Software Engineering) an umbrella process that enables a project team to accept, evaluate, and act on changes in a systematic manner |
| CRC (class-responsibility-collaborator) modeling - | (Software Engineering) an object-oriented modeling method that identifies and organizes classes are are relevant to a system |
| Defect removal efficiency (DRE) - | (Software Engineering) a nondimension ratio (between 0 and 1) that provides an indication of the degree to which errors are removed from software before it is released to end-users |
| Domain analysis - | (Software Engineering) an object-oriented software engineering activity that attempts to identify classes that are relevant to an entire application domain, rather than a specific application |