Explanation:

The computer abbreviation "OS" stands for "Operating System". An operating system is a software program that manages computer hardware and software resources, and provides common services for computer programs.

Operating System Functions:

1. Resource Management: The operating system manages the computer's resources, including the CPU, memory, disk space, and input/output (I/O) devices.

2. Process Management: The operating system manages processes (programs in execution), including scheduling, synchronization, and interprocess communication.

3. Memory Management: The operating system manages memory resources, including allocation, deallocation, and protection.

4. File Management: The operating system manages files and directories, including creation, deletion, and access control.

5. Security Management: The operating system provides security services, including user authentication, access control, and auditing.

Types of Operating Systems:

1. Single-user Operating Systems: These operating systems are designed for use by a single user, and are typically found on personal computers (PCs).

2. Multi-user Operating Systems: These operating systems are designed for use by multiple users, and are typically found on servers.

3. Real-time Operating Systems: These operating systems are designed for use in embedded systems, where timing is critical.

Some examples of popular operating systems include:

1. Microsoft Windows: A popular operating system for personal computers.

2. Apple macOS: An operating system for Apple's Macintosh computers.

3. Linux: A popular open-source operating system.

Conclusion:

In conclusion, "OS" is an abbreviation for "Operating System", which is a software program that manages computer hardware and software resources, and provides common services for computer programs. Operating systems perform various functions such as resource management, process management, memory management, file management, and security management. There are different types of operating systems, including single-user, multi-user, and real-time operating systems.

This is the most used abbreviated form in computer. OS is spelled as operating system and I think there is no strong reason behind it.