| Acronym | Meaning |
| EBMUD | East Bay Municipal Utility District (Oakland |
| EBNA | Epstein-Barr Virus Nuclear Antigen |
| EBO | Equivalent Bond Orbital |
| EBOM | Effective Bond-orbital Method |
| EBPR | Enhanced Biol. Phosphorus Removal |
| EBPVD | Electron Beam Physical Vapor Deposition |
| EBR | Experimental Breeder Reactor |
| EBRT | Empty-bed Residence Time |
| EBS | Engineered Barrier System (for Hazardous Waste Disposal) |
| EBS | Electron Backscattering |
| EBS | Extended Basis Set |
| EBSD | Electron Back Scatter Diffraction |
| EBSM | Extended Breathing Shell Model |
| EBSP | Electron Backscattering Pattern |
| EBT | Eccentric Bottom Tapping |
| EBT | Electron Beam Tomography |
| EBT | Extended Brillouin Theorem |
| EBV | Epstein-Barr Virus |
| EBW | Electron Beam Welding |
| EC | Enzyme Commission |
| EC | European Community |
| ECA | Equivalent Core Approximation |
| ECAE | Equal Channel Angular Extrusion |
| ECAFM | Electrochemical Atomic Force Microscopy |
| ECALE | Electrochemical Atomic Layer Epitaxy |
| ECAMSI | Electron Configuration Analysis For Many-system Interactions |
| ECAO | Environmental Criteria And Assessment Office |
| ECAP | Energy-compensated Atom Probe |
| ECAP | Equal Channel Angular Pressing |
| ECB | European Chemicals Bureau |
| ECBM | Enhanced Coalbed Methane (recovery) |
| ECBM | Extended Classical Over-barrier Model (in Calcns. On Inelastic Ion-atom Colisions) |
| ECC | Electrokinetic Capillary Chromatography |
| ECCD | Electron Cyclotron Current Drive |
| ECCD | Exciton-coupled Circular Dichroism |
| ECCES | Environmental Calculations Of Consequences From Energy Systems (model) |
| ECCF | Equilibrium Charge-charge Flux (model In Ir Spectra Calcns.) |
| ECCF | Exchange Correlated Crystal Field |
| ECCI | Electron Capture Chemical Ionization |
| ECCI | Electron Channeling Contrast Imaging |
| ECCLS | European Committee For Clinical Laboratory Standards |
| ECCM | Extended Coupled-cluster Method |
| ECCS | Emergency Core Cooling System |
| ECCS | Electro-coated Chromium Steel |
| ECD | Environmental Cleanup Division |
| ECD | Electron Capture Detector (gas Chromatography) |
| ECDIN | Environmental Chemicals Data And Information Network |
| ECDL | External-cavity Diode Laser |
| ECE | Electrical Conductivity Of Saturation Extract (soils) |
| ECEC | European Center For Environmental Communication |