A microkernel is a minimalistic approach to operating system design that focuses on providing only the essential services needed for the system to function. This includes basic functionalities like communication between processes and managing memory. By keeping the core of the operating system small, it allows for greater flexibility and easier maintenance, as additional services can be added as separate modules. In a microkernel architecture, most operating system services, such as device drivers and file systems, run in user space rather than kernel space. This separation enhances system stability and security, as a failure in one service does not compromise the entire system. Examples of microkernel-based operating systems include MINIX and QNX.