| Subject | English | Spanish |
| chem. | A1 | E173 |
| chem. | A1 | aluminio |
| chem. | A1 | CI pigment metal |
| tech. | 1 a negative kilo-calorie | fg |
| tech. | 1 a negative kilo-calorie | 1 frigoría |
| comp., MS | A1 notation | notación A1 (An alphanumeric convention for referencing the location of cells in a worksheet. The column is represented by a letter (A through IV, for a total of 256 columns) and the row is represented by a number (1 through 65536)) |
| life.sc. | A-1 soil | suelo A-1 |
| pharma. | a1-adrenoreceptor | adrenorreceptor α1 |
| pharma. | a1-adrenoreceptor | receptor adrenérgico α1 |
| pharma. | a1-adrenoreceptor | receptor α1 |
| pharma. | a1-adrenoreceptor | adrenoceptor α1 |
| gen. | anti-A1 antiserum | antisuero anti-A1 |
| transp. | atmospheric entry of a spacecraft in free fall using the aerodynamic maneuvering characteristics of the vehicle to influence the trajectory,at lift/drag ratios greater than 1 | reingreso planeado |
| transp. | atmospheric entry of a spacecraft in free fall using the aerodynamic maneuvering characteristics of the vehicle to influence the trajectory,at lift/drag ratios greater than 1 | reentrada planeada |
| gen. | CFE 1A | Acta de conclusión de la negociación sobre efectivos de personal de las Fuerzas Armadas Convencionales en Europa |
| UN | Coordinated Action on Small Arms campaign to limit traffic and use of handguns in Africa south of the SaharaA/C.1/53/L.41 | Mecanismo de medidas de coordinación en relación con las armas pequeñas |
| polit. | Directorate 1A - Human Resources | Dirección de Recursos Humanos |
| polit. | Directorate 1A - Human Resources | Dirección 1A - Recursos Humanos |
| polit. | Directorate 1A - Internal Market, Environment, Transport | Dirección de Mercado Interior, Medio Ambiente y Transporte |
| polit. | Directorate 1A - Internal Market, Environment, Transport | Dirección 1A - Mercado Interior, Medio Ambiente y Transporte |
| chem. | 1, 4, 5, 6, 7, 8, 8-Heptachloro-3a, 4, 7, 7a-tetrahydro-4, 7-endo-methanoindene | heptacloro |
| med. | influenza A virus subtype H1N1 | virus gripal AH1N1 |
| nat.sc., industr. | Management Committee Committee A1 - Systems of Socio-Technologies and Industrial Safety | Comité de gestión A1 - sistemas de sociotecnologías y seguridad industrial |
| met. | nitriding is applied to obtain a solid nitrogen solution in the matrix %1F BTL | la nitruración sirve para obtener una solución sólida de nitrógeno en la matriz |
| gen. | not to belong to a political group Rules of procedure of the European Parliament, OJEC L 49, art.30, 1 | no pertenecer a un grupo político |
| chem. | 1, 2, 4, 5, 6, 7, 8, 8-Octachloro-3a, 4, 7, 7a-tetrahydro-4, 7-endomethanoindane | clordán |
| chem. | 1, 2, 4, 5, 6, 7, 8, 8-Octachloro-3a, 4, 7, 7a-tetrahydro-4, 7-endomethanoindane | clordano |
| law | officials in grades A1 to A3 | funcionarios de grado A1 a A3 |
| chem. | the scum contained a considerable number of sulphate ions but no chloride ions %1F De Vries | el fango contenía grandes cantidades de iones sulfato, pero no de iones cloruro |
| polit. | Unit A1 | Presupuesto y Finanzas |
| gen. | Unit A1 | Unidad A1 |
| med. | vitamin A1 | vitamina A1 |
| med. | vitamin A1 | retinol |