A shared IP address contains several websites sharing the same IP address. Instead of having a unique (dedicated) address for every domain, you share an IP address with all accounts 

on the server. Using a shared IP address has its hazards. For example, if another website that is sharing the same IP address as you is blocked or blacklisted for whatever reason, your

website will also be blocked or blacklisted. 

Using a dedicated IP address means that your site is the only one on the internet using that particular IP address. Using a dedicated IP address is a good option if your website wants to 

grow its IP reputation without fear that their IP will be blocked or blacklisted from something that's not in your control.