| Acronym | Definition |
|---|
| B | Big |
| B | Bit |
| B | Billion |
| B | Byte |
| B | Above Average grade |
| B | Reverse Side, Record |
| B | Back (chat) |
| B | Black |
| B | Business |
| B | Book |
| B | Blue |
| B | Butt (welded joint type) |
| B | Bad (worst CD condition) |
| B | Base (transistor; electronics) |
| B | Bottom |
| B | Brown |
| B | British |
| B | Bank |
| B | Block |
| B | Born |
| B | Be |
| B | Bag |
| B | Blank |
| B | Bass |
| B | Boat (Stores 100 code) |
| B | Bomber (US military aircraft designation; as in B-52) |
| B | Bridge |
| B | Bible |
| B | Beta (2nd brightest star in a constellation) |
| B | Before |
| B | Bold Text (HTML) |
| B | Britain |
| B | Both |
| B | Bat |
| B | Bureau |
| B | Bishop |
| B | Bravo |
| B | Biological |
| B | Bachelor |
| B | Brick |
| B | Barn |
| B | Individual (IRB) |
| B | Binary |
| B | Bandwidth |
| B | Bombardier |
| B | Bore (French: Boron) |
| B | Bulb |
| B | Birmingham (postcode, United Kingdom) |
| B | Berlin (auto license plate) |
| B | Brightness |
| B | Boeing |
| B | Birthday (Beatles song) |
| B | Belgium (International Auto Identification) |
| B | Bolivar (unit of currency) |
| B | Bilateral |
| B | Basso |
| B | Bucharest (Romanian state capital) |
| B | Balboa (currency of Panama) |
| B | Biography (library code) |
| B | Y-Intercept (from the equation y = mx + b) |
| B | Bale |
| B | Boron |
| B | Blade (comic; movie) |
| B | Beam (naval architecture; width of hull) |
| B | Baht (currency of Thailand) |
| B | Nova Scotia (Canada Post designation) |
| B | Baume (relating to the propriety of hydrometer measurements) |
| B | Bacillus |
| B | Baroness |
| B | Bowled |
| B | Brazing |
| B | Tical (another name for baht, Thai currency) |
| B | Billable |
| B | Bezier (spline curve) |
| B | Bearer Channel (ISDN) |
| B | At or Below (constrained altitude) |
| B | Biocide |
| B | Betaxolol (blood pressure drug) |
| B | Blink Reflex (neurology) |
| B | Panamanian Balboa (national currency) |
| B | Semipostal (philatelic catalog prefix for non-standard stamps) |
| B | Butut (1/100 division of the dalasi, the Gambian currency) |
| B | Barnabites (religious order) |
| B | Magnetic Field Density (physics) |
| B | Betopic (same as Betaxolol) |
| B | Banknote Corporation of America (philatelic mark for company stamps) |
| B | B computer language (Ken Thompson; predecessor to C) |
| B | Bone Marrow-Derived Lymphocyte |
| B | Federal Reserve Bank of New York City (designates original spot of circulation of a bill) |
| B | Bordetella Bacterium |
| B | Switzerland Postmark (for letters going to Sardinia) |
| B | US Domestic Stamp Rate (18 cents, issued 15 May 1981) |
| B | Cross-Over Barrier Pattern (US DoD) |