CPU one of the main components of a server. The server that your site is housed on has one or multiple CPUs, just like on your home computer. The larger the capacity of the CPU, the more information it can store and process.
If your website hosted on shared hosting package, then these CPU resources will be divided. The requests will be processed in the order they are received. However, the CPU will be able to process multiple requests at once, and can use time sling to ensure the requests are handled very quickly.
If your website receives large, or high traffic, then we recommend choosing a hosting plan with higher CPU such as a VPS or dedicated server plan.