| Photochemical pollutants | (Environmental Engineering) Chemicals which react photochemically (in the presence of sunlight) to destroy ozone in the stratosphere. |
| Runoff | (Environmental Engineering) The water that flows overland to lakes or streams during and shortly after a precipitation event. |
| Siting | (Environmental Engineering) Obtaining government (federal, state, and local) permission to construct an environmental processing, treatment, or disposal facility at a given site. |
| Species | (Environmental Engineering) In chemistry, an ion or molecule in solution. |
| Sterilization | (Environmental Engineering) The destruction or inactivation of all microorganisms. See Disinfection. |
| Stratosphere | (Environmental Engineering) The atmosphere from approximately 12 km to 70 km. The temperature of the atmosphere increases in this region.Strong acid |
| Substrate level phosphorylation | (Environmental Engineering) The synthesis of the energy storage compound adenosine triphosphate (ATP) from adenosine diphosphate (ADP) using organic substrates without molecular oxygen. |
| Wastewater | (Environmental Engineering) Consumed or used water from a municipality or industry that contains dissolved and/or suspended matter. |
| 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. |
| 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) - |