Shared Hosting refers to a web hosting service where many websites reside on one web server connected to the Internet. This means that one physical server and its available resources hosted are shared among many users. Actually, on the shared hosting platform each customer has his own limit on particular services like disk space, monthly traffic, email accounts, FTP accounts, databases etc.
On the other hand, all performance resources on a physical machine (server) are shared.
In shared hosting, the provider is generally responsible for managing servers, installing server software, security updates, technical support, and other aspects of the service.