| Biofilm | (Environmental Engineering) A film of microorganisms attached to a surface, such as that on a trickling filter, rotating biological contactor, or rocks in natural streams. |
| Biogeochemical cycle | (Environmental Engineering) The cycle of elements through the biotic and abiotic environment. |
| Biosynthesis | (Environmental Engineering) Catabolism, the production of new cellular materials from other organic or inorganic chemicals. |
| Baseline - | (Software Engineering) a point at which some deliverable produced during the software engineering process is put under formal change contro |
| Basis path testing - | (Software Engineering) a white box test case design technique that used the algorithmic flow of the program to design tests |
| Basis set - | (Software Engineering) the set of tests derived using basis path testingBehavioral modeling - |
| Beta testing - | (Software Engineering) testing that is conducted by the user |
| Black box testing - | (Software Engineering) testing that does not focus on the internal details of the program but uses external requirements |
| Boundary value analysis - | (Software Engineering) a black box testing method that designs test cases that exercise data boundaries |
| Bounding - | (Software Engineering) removing ambiguity from specification |