| Acronym | Meaning |
| BCT | Best Control Technology |
| BCT | Best Conventional Technology |
| BCT | Body Centered Tetragonal |
| BCUT | Burden CAS And University Of Texas |
| BCV | Bovine Coronavirus |
| BD | Brueckner (orbitals With) Double (substitution) (in Electron Correlation) |
| BDA | Biotinylated Dextran Amine |
| BDAT | Best Demonstrated Available Technology |
| BDCT | Best Demonstrated Control Technology |
| BDD | Boron-doped Diamond |
| BDE | Bond Dissociation Energy |
| BDH | British Drug House |
| BDNF | Brain-derived Neurotrophic Factor |
| BDOC | Biodegradable Dissolved Organic Carbon |
| BDST | Bed-depth Service Time |
| BDT | Best Demonstrated Technology |
| BDT | Brueckner (with) Double (and) Triple (substitutions) |
| BDT | Brittle-ductile Transition |
| BDTQ | Brueckner (with) Double |
| BDTT | Brittle-to-ductile Transition Temperature |
| BEA | Bureau Of Economic Analysis |
| BEA | Binary Encounter Approximation |
| BEAR | Business And Environmentalists In An Alliance For Recycling |
| BEAR | Biological Effects Of Atomic Radiation |
| BEAUTY | BLAST Enhanced Alignment Utility |
| BEBC | Big European Bubble Chamber |
| BEBO | Bond Energy Bond Order Method |
| BEBO/R | Relaxed Bond Energy-bond Order Method |
| BEC | Bose-Einstein Condensation |
| BEEM | Ballistic Electron Emission Microscopy |
| BEES | Ballistic Electron Emission Spectroscopy |
| BEFS | Berkeley Extreme And Far-UV Spectrometer |
| BEHP | Bis(2-ethylhexyl) Phthalate |
| BEI | Biological Exposure Indices |
| BEI | Backscattered Electron Imaging |
| BEIA | Biomedical And Environmental Information Analysis |
| BEIR | Advisors Committee On The Biological Effects Of Ionizing Radiation |
| BEIS | Biogenic Emissions Inventory System (US EPA) |
| BEJ | Best Engineering Judgement |
| BEJ | Best Expert Judgement |
| BEKP | Backscattered Electron Kikuchi Pattern |
| BELLE | Biological Effects Of Low Level Exposures |
| BEM | Boundary Element Method |
| BEPR | Biological Excess Phosphorus Removal |
| BER | Base Excision Repair |
| BER | Bit Error Rate |
| BERG | Building Effects Review Group |
| BERM | Biological And Environmental Reference Materials |
| BESB | Biological Environmental Specimen Banking |
| BESOI | Bonded And Etched-back Silicon-on-insulator |