Recently I heard the term meta-operating system while I was learning ros. Could you please help me to differentiate between operating system and meta-operating system?
What ROS is and is not is best explained in this paper.
To cite the intodruction at ros.org:
It provides the services you would expect from an operating system, including hardware abstraction, low-level device control, implementation of commonly-used functionality, message-passing between processes, and package management. It also provides tools and libraries for obtaining, building, writing, and running code across multiple computers.
You'll also find a good explanation in this wiki. The basic difference is that a meta operating system is built on top of the operating system and allows different processes (nodes) to communicate with each other at runtime.