| BOS | Backup Operating System | In English | |
| BOS | Belgrade Open School | In English | → Higher education, universities |
| BOSO | Ballistic Orbital Support Operations | In English | |
| BOT | Beginning Of Tape | In English | |
| BOW | Bill Of Work | In English | |
| BP | Boiling Point | In English | |
| BP | Boilerplate | In English | |
| BP | Blueprint | In English | |
| BP | Blood Pressure | In English | → Blood and circulatory system |
| BP | Base Plate | In English | |
| BP | Barber Pole | In English | |
| BP | Bandpass | In English | |
| BP | Buttock Plane | In English | |
| BP | Back Pressure | In English | |
| BP | Bletchley Park | In English | |
| BPAG | Bullous Pemphigoid Antigen | In English | → Biochemistry, biophysics |
| BPAS | Bulletin of Pure and Applied Science | In English | → Serial publications, periodicals → Physics |
| BpBeS | Biophysics and Bioengineering Series | In English | → Serial publications, periodicals → Biochemistry, biophysics |
| BPC | Backpressure Control | In English | |
| BPC | Boost Protective Cover | In English | |
| BPD | Baseline Program Document(ation) | In English | |
| BPEL | Business Process Execution Language | In English | → Trade |
| BPEL4WS | Business Process Execution Language for Web Services | In English | → Networks, communication → Economics |
| BPI | Boost Phase Intercept | In English | |
| BpJ | Biophysical Journal | In English | → Serial publications, periodicals → Biochemistry, biophysics |
| BPM | Business Process Management | In English | → Management |
| BPM | Business Performance Management | In English | → Management |
| BPM | Business Process Model(l)ing | In English | → Management → Economics |
| BPML | Business Process Management Language | In English | → Programming languages → Data |
| BPML | Business Process Markup Language | In English | → Programming languages → Economics |
| BPML | Business Process Modelling Language | In English | → Programming languages → Economics |
| BPMS | Blood Pressure Measuring System | In English | → Blood and circulatory system |
| BPMS | Business Process Management Systems | In English | → Management |
| BPO | Business Process Outsourcing | In English | → Economics |
| BPO | Blanket Purchase Order | In English | |
| BPQL | Business Process Query Language | In English | → Programming languages → Economics |
| BPR | Business Process Redesign | In English | |
| BPR | Bimonthly Progress Report | In English | |
| BPR | Bypass Ratio | In English | |
| BPS | Boost Propulsion System | In English | → Spaceflight engineering, astronautics |
| BPS | Biological Physics Series | In English | → Serial publications, periodicals → Biochemistry, biophysics |
| BPS | Bureau of Product Standards | In English | → Standardization |
| BPSK | Biphase Shift Key(ing) | In English | |
| BPT | Body Point | In English | |
| BPV | Bipropellant Valve | In English | → Spaceflight engineering, astronautics |
| BPWG | Blood Products Working Group | In English | → Organizations and associations → Pharmacology, toxicology |
| BR | Bit Rate | In English | |
| BRAN | Broadband Radio Access Network | In English | → Telecommunications |
| BRAVO | Business Risk And Value if Operation in space | In English | → Spaceflight engineering, astronautics |
| BRC | British Retail Consortium | In English | → Organizations and associations → Trade |
| BRCC | Biomedical Reference Collection : Comprehensive Edition | In English | → Libraries → Biological sciences → Biotechnology → Medicine |
| BRCPS | Biological Reviews of the Cambridge Philosophical Society | In English | → Serial publications, periodicals → Biological sciences |
| BRCS | Basic Reference Coordinate System | In English | |
| BRDF | Bidirectional Reflectance Distribution Function | In English | |
| BRE | Building Research Establishment | In English | → Building |
| BRF | Band Rejection Filter | In English | |
| BRG | Business Region Göteborg | In English | → Economics |
| BRI | Basic Rate Interface | In English | → Telecommunications |
| BRICKS | Building Ressources for Integrated Cultural Knowledge Service | In English | → Civilization, culture, progress |
| BrJPh | Brazilian Journal of Physics | In English | → Serial publications, periodicals → Physics |
| BRL | Ballistic Research Laboratory | In English | → Research institutes → Military engineering |
| BRM | Baseline Reference Mission | In English | |
| BRM | Biological Research Module | In English | → Biological sciences |
| BRMIC | Behavior Research Methods, Instruments and Computers | In English | → Serial publications, periodicals → Psychology → Computer science |
| BRRS | Banana River Repeater Station | In English | |
| BRS | Bottom Right Side | In English | |
| BS | Backup Subsystem | In English | |
| BS | Beam Splitter | In English | |
| BS | Block Specification | In English | |
| BS | British Standard | In English | → Standardization |
| BSA | Battery Bus Solar Array | In English | → Vehicle engineering |
| BSA | British Sociological Association | In English | → Associations → Sociology |
| BSA | Business Software Alliance | In English | → Organizations and associations → Software |
| BSAVA | British Small Animal Veterinary Association (www.bsavastore.com) | In English | → Associations → Veterinary medicine |
| BSC | British Society of Cinematographers (www.bscine.com) | In English | → Organizations and associations → Cinema, movies |
| BSC | Brake Skid Controller | In English | |
| BSC | Base Station Controller | In English | → Telecommunications |
| BSCM | Business Service Configuration Manager | In English | → Hardware |
| BSCS | Budapest Semester in Cognitive Science | In English | → Higher education, universities → Psychology → Neurology |
| BSCS | Bachelor of Science in Computer Science | In English | → Higher education, universities → Computer science |
| BSD | Ballistic Systems Division | In English | |
| BSD | Berkeley System Distribution | In English | → Operating systems |
| BSD | Berkeley Software Distribution | In English | → Operating systems |
| BSDP | Booster-Stage Discharge Pressure | In English | |
| BSE | Booster Systems Engineer | In English | |
| BSE | Bovine Spongiform Encephalopathy = ESB | Encéphalopathie Spongioforme Bovine | In French = BSE | Bova Spongoforma Encefalopatio | In Esperanto = EEB | Encefalopatía Espongiforme Bovina | In Portuguese = BSE | Bovine Spongiforme Enzephalopathie | In German = BSE | Bovin spongiform ensefalopati | In Turkish = ESB | Encephalopathia Spongiforme Bovin | In Interlingua = BSE | Boviene spongiforme encefalopathie | In Dutch = GSE | Goveđa spongiformna encefalopatija | In Serbo-Croatian = ESB | Encefalopatia Spongiforme Bovina | In Italian |
In English | → Veterinary medicine |
| BSEC | Black Sea Economic Co-operation | In English | → International relations |
| BSEE | Bachelor of Science in Electrical Engineering | In English | → Higher education, universities → Electrical engineering |
| BSGE | BAchelor of Science in General Engineering | In English | |
| BSI | Basic Shipping Instruction | In English | |
| BSI | Boeing Services International | In English | |
| BSI | Booster Situation Indicator | In English | |
| BSI | British Standards Institution | In English | → Standardization |
| BSI | BioSystems International (www.biosys-intl.com) | In English | → Biotechnology |
| BSM | Beam-Steering Mechanism | In English | |
| BSM | Booster Separation Motor | In English | |
| BSMD | Bahrain Standards & Metrology Directorate | In English | → Standardization |
| BSME | Bachelor of Science in Mechanical Engineering | In English | |
| BSML | Bioinformatic Sequence Markup Language | In English | → Data → Biological sciences |
| BSOAS | Bulletin of the School of Oriental and African Studies | In English | → Serial publications, periodicals → Language, linguistics, literature → Geography, biography, history |
| BSOS | Bulletin of the School of Oriental Studies | In English | → Serial publications, periodicals → Language, linguistics, literature → Geography, biography, history |
| BSP | Business System Planning | In English | |
| BSR | BITE Status Register | In English | |
| BSR | Basic System Release | In English | |
| BSRA | British Ship Research Association | In English | → Associations → 6295 |
| BSRAEM | Black Sea Regional Agency for Energy Management | In English | → Energy economics |
| BSREC | Black Sea Regional Energy Centre | In English | → Energy economics |
| BSRIA | Building Services Research and Information Association | In English | → Organizations and associations → Building |
| BSRM | Booster Solid Rocket Motor | In English | |
| BSS | Backup System Services | In English | |
| BSS | (The) Bishop Strachan School | In English | → Education |
| BSS | Bangladesh Sangbad Sangstha | In English | |
| BSSA | Bulletin of the Seismological Society of America | In English | → Serial publications, periodicals → Seismology, earthquakes |
| BSSM | British Society for Sexual Medicine | In English | → Organizations and associations → Sexual problems → Urology → Applied sciences, technology |
| BSTI | Bangladesh Standards and Testing Institution | In English | → Standardization |
| BSTS | Boost Surveillance Tracking System | In English | |
| BSW | BFS Software | In English | → Software |
| BT | Burn Time | In English | |
| BT | Business Telecommunications | In English | → Telecommunications |
| BT | British Telecommunications | In English | → Telecommunications |
| BT | Technical Board | In English | |
| BTB | Biblical Theology Bulletin | In English | → Serial publications, periodicals → Religion, theology |
| BTC | Business TeleCommunications | In English | → Telecommunications |
| BTC | Bulgarian Telecommunication Company | In English | → Telecommunications |
| BTC | Binary Time Code | In English | → Computer science |
| BTC | Bus Tie Contractor | In English | |
| BTE | Bench Test Equipment | In English | |
| BTE | British Telecommunications Engineering | In English | → Serial publications, periodicals → Telecommunications |
| BTH | Below The Horizon | In English | |
| BTMS | Body Temperature Measuring System | In English | |
| BToIT | Bulletin of the Tokyo Institute of Technology | In English | → Serial publications, periodicals → Applied sciences, technology |
| BTok | Bulletin of the Tokyo Astronomical Observatory | In English | → Serial publications, periodicals → Astronomy |
| BTR | Burn Time Remaining | In English | |
| BTR | Bus Transfer | In English | → Computer science |
| BTRC | Bankstown Trotting Recreation Club | In English | → Organizations and associations → Entertainment |
| BTRC | Blacksburg Tactical Research Center (www.btrc.net) | In English | → Entertainment |
| BTRC | Bio-Tek Research Consultants (www.btrc.com) | In English | → Biotechnology → Consulting |
| BTRC | Bluetooth Remote Control | In English | → Telecommunications |
| BTS | Base Transceiver Station | In English | → Telecommunications |
| BTTF | Technical Board Task Force | In English | |
| BTU | Bus Terminal Unit | In English | → Computer science |
| BTU | British Thermal Unit | In English | |
| BUAAJ | Beijing University Aeronautics and Astronautics Journal | In English | → Serial publications, periodicals → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| BUBes | Bulletin of the University of Besancon Observatory | In English | → Serial publications, periodicals → Astronomy |
| BUC | Backup Computer | In English | → Hardware |
| BUFC | Backup Flight Controller | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| BUIC | Backup Interceptor Control | In English | |
| BuIPS | Bulletin of the Israel Physical Society | In English | → Serial publications, periodicals → Physics |
| BuLMS | Bulletin of the London Mathematical Society | In English | → Serial publications, periodicals → Mathematics |
| BUN | BITE Update Notice | In English | |
| BUN | Blood Urea Nitrogen | In English | → Physiology |
| BUOU | Backup Optical Unit | In English | |
| BUR | Backup Rate | In English | |
| BuSSA | The Bulletin of the Seismological Society of America | In English | → Serial publications, periodicals → Seismology, earthquakes |
| BUTE | Budapest University of Technology and Economics | In English | → Economics → Higher education, universities → Engineering, technology |
| BV | Balanced Voltage | In English | |
| BV | Boost Vehicle | In English | |
| BV | Booster Vehicle | In English | |
| BVC | Boost Voltage Converter | In English | |
| BVI | Blood Volume Index | In English | → Blood and circulatory system |
| BVol | Bulletin of Volcanology | In English | → Serial publications, periodicals → 55121 |
| BW | Bridge Wire | In English | |
| BW | Beam Width | In English | |
| BW | Bandwidth | In English | |
| BWG | Birmingham Wire Gauge | In English | |
| BWO | Backward Wave Oscillator | In English | |
| BWP | Biotechnology Working Party | In English | → Organizations and associations → Biotechnology |
| BWR | Boiling Water Reactor = SWR | Siedewasserreaktor | In German = REB | Réacteur à Eau Bouillante | In French |
In English | → Nuclear technology |
| BXML | Backbase eXtensible Mark-up Language | In English | → Programming languages |
| BYam | Bulletin of the Yamagata University | In English | → Serial publications, periodicals |
| C | Cytidine | In English | → Genetics → Biochemistry, biophysics |
| C | Cysteine = C | Cisteïna | In Catalan = C | Cystein | In Czech = C | Cystein | In German = C | Cisteína | In Spanish = C | Cisteino | In Esperanto = C | Cystéine | In French = C | 시스테인 | In Korean = C | Sistein | In Indonesian = C | Cisteina | In Italian = C | ציסטאין | In Hebrew = C | Cisteīns | In Latvian = C | Cystein | In Letzeburgesh = C | Cisteinas | In Lithuanian = C | Cisztein | In Hungarian = C | Cysteïne | In Dutch = C | システイン | In Japanese = C | Cystein | In Norwegian = C | Cysteina | In Polish = C | Cisteína | In Portuguese = C | Цистеин | In Russian = C | Kysteiini | In Finnish = C | Cystein | In Swedish = C | Цистеїн | In Ukrainian = C | 半胱氨酸 | In Chinese |
In English | → Biochemistry, biophysics |
| C | Carbon = C | Carbone | In French = C | Koolstof | In Afrikaans = C | كربون | In Arabic = C | Carbonu | In Asturian = C | Karbon | In Azerbaijani = C | Вуглярод | In Belarusian = C | Въглерод | In Bulgarian = C | কার্বন | In Bengali = C | Carboni | In Catalan = C | Carboniu | In Corsican = C | Uhlík | In Czech = C | Carbon | In Welsh = C | Carbon | In Danish = C | Kohlenstoff | In German = C | Άνθρακας | In Greek = C | Karbono | In Esperanto = C | Carbono | In Spanish = C | Süsinik | In Estonian = C | Karbono | In Basque = C | کربن | In Persian = C | Hiili | In Finnish = C | Carboni | In Friulian = C | Carbón | In Irish = C | Gualan | In Galician = C | Carbono | In Galician = C | કાર્બન | In Gujarati = C | פחמן | In Hebrew = C | कार्बन | In Hindi = C | Ugljik | In Croatian = C | Kabòn | In Haitian Creole = C | Szén | In Hungarian = C | Ածխածին | In Armenian = C | Carbon | In Interlingua = C | Karbon | In Indonesian = C | Karbo | In Ido = C | Kolefni | In Icelandic = C | Carbonio | In Italian = C | 炭素 | In Japanese = C | tabno | In Lojban = C | ಇಂಗಾಲ | In Kannada = C | 탄소 | In Korean = C | Karbon | In Kurdish = C | Carbonium | In Latin = C | Kuelestoff | In Letzeburgesh = C | Koolstof | In Limburgish = C | Carbòni | In Lombard = C | Kaboni | In Lingala = C | Anglis | In Lithuanian = C | Ogleklis | In Latvian = C | Waro | In Māori = C | Јаглерод | In Macedonian = C | കാര്ബണ് | In Malayalam = C | Нүүрстөрөгч | In Mongolian = C | कार्बन | In Marathi = C | Karbon | In Malay = C | Tecolli | En Nahuatl = C | Kohlenstoff | In Low German = C | Koolstof | In Dutch = C | Karbon | In Nynorsk = C | Karbon | In Norwegian = C | Karbo | NOV = C | Carbòni | In Occitan = C | Węgiel | In Polish = C | Carbono | In Portuguese = C | K'illimsayaq | In Quechua = C | Carbon | In Romanian = C | Углерод | In Russian = C | Carbòniu | In Sicilian = C | Ugljenik | In Serbo-Croatian = C | Uhlík | In Slovak = C | Ogljik | In Slovenian = C | Karboni | In Albanian = C | Угљеник | In Serbian = C | Karbon | In Sundanese = C | Kol | In Swedish = C | Kaboni | In Swahili = C | கரிமம் | In Tamil = C | Карбон | In Tajik = C | คาร์บอน | In Thai = C | Karbon | In Tagalog = C | Karbon | In Turkish = C | Вуглець | In Ukrainian = C | Uglerod | In Uzbek = C | Cacbon | In Vietnamese = C | Carboun | In Vlaams = C | Carbone | In Walloon = C | 碳 | In Wu Chinese = C | קוילנשטאף | In Yiddisch = C | 碳 | In Chinese |
In English | → Chemistry |
| C | Cytosine = C | Cytosine | In French = C | Citosina | In Catalan = C | Cytosin | In Czech = C | Cytosin | In Danish = C | Cytosin | In German = C | Citosina | In Spanish = C | Citozino | In Esperanto = C | Citosina | In Galician = C | Sitosin | In Indonesian = C | Citosina | In Italian = C | ציטוזין | In Hebrew = C | Citozinas | In Lithuanian = C | Cytosine | In Dutch = C | シトシン | In Japanese = C | Cytosin | In Norwegian = C | Cytozyna | In Polish = C | Citosina | In Portuguese = C | Цитозин | In Russian = C | Citozin | In Slovenian = C | Цитозин | In Serbian = C | Citozin | In Serbo-Croatian = C | Sytosiini | In Finnish = C | Cytosin | In Swedish = C | Cytosine | In Vietnamese = C | Sitozin | In Turkish = C | Цитозин | In Ukrainian = C | 胞嘧啶 | In Chinese |
In English | → Genetics → Biochemistry, biophysics |
| C3NeF | C3 Nephritic Factor | In English | → Biochemistry, biophysics |
| Ca | Calcium = Ca | Kalsium | In Afrikaans = Ca | Calciu | In Asturian = Ca | ক্যালসিয়াম | In Bengali = Ca | Kalcijum | In Bosnian = Ca | Калций | In Bulgarian = Ca | Calci | In Catalan = Ca | Vápník | In Czech = Ca | Calciu | In Corsican = Ca | Calsiwm | In Welsh = Ca | Calcium | In Danish = Ca | Calcium | In German = Ca | Kaltsium | In Estonian = Ca | Ασβέστιο | In Greek = Ca | Calcio | In Spanish = Ca | Kalcio | In Esperanto = Ca | Kaltzio | In Basque = Ca | Calcium | In French = Ca | Calci | In Friulian = Ca | Kelkium | In Manx = Ca | Calcio | In Galician = Ca | 칼슘 | In Korean = Ca | Կալցիում | In Armenian = Ca | काल्सियम | In Hindi = Ca | Kalcij | In Croatian = Ca | Kalcio | In Ido = Ca | Kalsium | In Indonesian = Ca | Kalsín | In Icelandic = Ca | Calcio | In Italian = Ca | Kalisi | In Swahili = Ca | Kalsyòm | In Haitian Creole = Ca | Kalsiyûm | In Kurdish = Ca | Calcium | In Latin = Ca | Kalcijs | In Latvian = Ca | Kalzium | In Letzeburgesh = Ca | Kalcis | In Lithuanian = Ca | bogjinme | In Lojban = Ca | Kalcium | In Hungarian = Ca | Калциум | In Macedonian = Ca | കാല്സ്യം | In Malayalam = Ca | Konupūmā | In Māori = Ca | Kalsium | In Malay = Ca | Tenextepoztli | En Nahuatl = Ca | Calcium | In Dutch = Ca | カルシウム | In Japanese = Ca | Kalsium | In Norwegian = Ca | Kalsium | In Nynorsk = Ca | Calci | In Occitan = Ca | Kalsiy | In Uzbek = Ca | Calcium | In Low German = Ca | Wapń | In Polish = Ca | Cálcio | In Portuguese = Ca | Calciu | In Romanian = Ca | Isku q'illay | In Quechua = Ca | Кальций | In Russian = Ca | Kalciumi | In Albanian = Ca | Calciu | In Sicilian = Ca | Vápnik | In Slovak = Ca | Kalcij | In Slovenian = Ca | Калцијум | In Serbian = Ca | Kalcij | In Serbo-Croatian = Ca | Calcium | In Saterland Frisian = Ca | Kalsium | In Sundanese = Ca | Kalsium | In Finnish = Ca | Kalcium | In Swedish = Ca | கல்சியம் | In Tamil = Ca | కాల్షియమ్ | In Telugu = Ca | แคลเซียม | In Thai = Ca | Canxi | In Vietnamese = Ca | Калсий | In Tajik = Ca | Kalsiyum | In Turkish = Ca | Кальцій | In Ukrainian = Ca | 钙 | In Chinese |
In English | → Chemistry |
| CA | Cancer Antigen | In English | → Biochemistry, biophysics → Oncology |
| CA | Critical Analysis | In English | |
| CA | Cost Account | In English | → Prices |
| CA | Corrective Action | In English | |
| CA | Contract Award | In English | → 3474 |
| CA | Contract Advice | In English | → 3474 |
| CA | Cone Angle | In English | |
| CA | Completion of Assembly | In English | → Engineering, technology |
| CA | Carrier Aircraft | In English | → Aeronautics, aircraft |
| CAA | Civil Aeronautics Administration | In English | → Public administration, government → Aeronautics, aircraft |
| CAA | Composite Audio Amplifier | In English | |
| CAA | Cost Account Authorization | In English | → Prices |
| CAA | Colorado Assessors Association (www.e-caa.com) | In English | → Associations → 332 |
| CAA | Computational Aeroacoustics | In English | → Computer-based techniques → Aerodynamics → Acoustics |
| CAA | Component Application Architecture | In English | → Software |
| CAAB | Canadian Association of Animal Breeders | In English | → Associations |
| CAALIS | Computer-Aided Assembly-Line Inspection System | In English | → Computer-based techniques |
| CAAML | Canadian Avalanche Association Markup Language | In English | → Software → Earth sciences |
| CAAO | Connecticut Association of Assessing Officers (www.caao.com) | In English | → Associations → 332 |
| CAAS | Centre for Arabic and African Studies | In English | → Language, linguistics, literature → Geography, biography, history |
| CAAT | Computer-Aided Assembly Tool | In English | → Computer-based techniques |
| CAAT | (Johns Hopkins) Center for Alternatives to Animal Testing (http://caat.jhsph.edu) | In English | → Organizations and associations → Medicine |
| CAB | Complement Activation Blocker | In English | → Biochemistry, biophysics → Immunology and allergy |
| CAB | Congregation of Alexian Brothers | In English | → 272 |