| Subject | English | Bulgarian |
| comp., MS | Microsoft Disk Operating System | дискова операционна система на Microsoft (A Microsoft computer operating system with a command-line interface that is used to control many internal computer functions, such as running programs and organizing and maintaining files) |
| comp. | mobile operating system | мобилна платформа |
| comp. | mobile operating system | мобилна операционна система |
| gen. | mobile operating system | мобилна ОС |
| comp., MS | MS-DOS operating system | операционна система MS-DOS (A Microsoft computer operating system with a command-line interface that is used to control many internal computer functions, such as running programs and organizing and maintaining files) |
| comp., MS | operating system | операционна система (The software that controls the allocation and usage of hardware resources such as memory, central processing unit (CPU) time, disk space, and peripheral devices. The operating system is the foundation on which programs are built) |
| comp., MS | operating system | операционна система (The software that controls the allocation and usage of hardware resources such as memory, central processing unit (CPU) time, disk space, and peripheral devices. The operating system is the foundation on which programs are built) |
| construct. | operating system | операционна система |