| Ethers | (Environmental Engineering) An organic compound which has two hydrocarbon groups bound by an interior oxygen atom. The general formula is R'-O-R". |
| Eucaryotic organisms | (Environmental Engineering) Organisms which possess a nuclear membrane. This includes all known organisms except viruses and bacteria. |
| Effort - | (Software Engineering) the work-time product (e.g., person-days) associated with a project |
| Engineering change order (ECO) - | (Software Engineering) a mini-specification that describes the technical aspects of a change |
| Enhancement - | (Software Engineering) an extension of functional or performance requirements |
| Equivalence partitioning - | (Software Engineering) a black-box testing method |
| Errors - | (Software Engineering) a lack of conformance found before software is delivered to the customer |
| Estimation - | (Software Engineering) a project planning activity that attempts to project effort and cost for a software project |
| Extreme programming - | (Software Engineering) an agile process model that emphasizes scenario-based planning, incremental delivery, refactoring, pair programming and continuous testing. |
| Elastic Shortening | (Concrete Engineering) The shortening of a member in pre-stressed concrete which occurs on the application of forces induced by prestressing. |