1. 磁盘操作系统
DOS is the part of a computer operating system that controls and manages files and programs stored on disk. DOS is an abbreviation for (缩略=) 'disk operating system'.

1. the federal department in the United States that sets and maintains foreign policies

e.g. the Department of State was created in 1789

Synonym: Department of StateUnited States Department of StateState DepartmentState