| Bachelor of Science | licenciado en ciencias |
| bachelor party | despedida de soltero |
| bachelor's button | margarita |
| bachelor's degree | bachillerato |
| bachelorette | soltera |
| bachelorette party | despedida de soltera |
| bachelorhood | celibato |
| Bachianas brasileiras | Bachianas brasileiras |
| Bachir Gemayel | Bashir Gemayel |
| bacilli | bacterias |
| bacillus | bacilo |
| Bacillus anthracis | Bacillus anthracis |
| Bacillus Calmette-Guérin | Bacillus Calmette-Guerin |
| back | defensa |
| back away | alejarse |
| back cover | contraportada |
| back door | puerta trasera |
| back down | echarse atrás |
| Back draught | Acojinamiento |
| back fire | contrafuego |
| Back for the First Time | Back For The First Time |
| Back in Black | Back In Black |
| back of beyond | quinto pino |
| back of the head | nuca |
| back off | echarse atrás |
| back out | echarse atrás |
| back pedaling | marcha atrás |
| back pedalling | marcha atrás |
| Back rank checkmate | Mate del pasillo |
| back road | camino vecinal |
| back seat | asiento trasero |
| Back streets | Barrios bajos |
| back support | respaldo |
| back talk | impertinencia |
| Back to Basics | Back to Basics |
| Back to Basics Tour | Back To Basics World Tour |
| Back to Bedlam | Back to Bedlam |
| Back to Black | Back to Black |
| back to front | al revés |
| Back To Jerusalem movement | Retorno a Jerusalén |
| Back to the Egg | Back to the Egg |
| Back to the Future | Regreso al futuro |
| Back to the Future Part II | Back to the future II |
| Back to the Future Part III | Back To The Future III |
| Back to the Future trilogy | Regreso al futuro |
| back up | embotellamiento |
| back vowel | vocal posterior |
| back window | ventanilla trasera |
| back yard | traspatio |
| back-formation | formación regresiva |
| back-to-back | espaldera |
| back-up | apoyo |
| back-up file | fichero de reserva |
| back-up light | luz de retroceso |
| backache | dolor de espalda |
| Backbeat | Backbeat |
| backbite | calumniar |
