This is a 32 bit (IPv4) or 128 bit (IPv6) address that identifies a specific host. The IP address of a website is the address of the associated webserver and your IP address shown on IP Checker is the address that your internet provider has given to you.
The Internet Assigned Numbers Authority (IANA) is the organization oversees global IP address allocation. IP address ranges are assigned to countries and internet providers worldwide. The local internet providers in finally distribute their address share to companies or individuals.
Each public IP address is uniqe and points to a specific physical location on earth. This is essiential for the internet to funnction, otherwise it wouldn't be possible for IP packets to reliably reach a specific destination.
It is technically impossible to use faked IP addresses in internet communications. This is because your internet provider would discard faked IP packets right away. Even if these packets would reach the destination, no reply packet would come back to you. This means that if you receive an IP packet, you can be sure where the packet came from. If it was a malicious data packet it is therefore possible to contact the associated internet provider shown in the IP Checker results and make an abuse report.
In the case of dynamically assigned IP addresses however, only the internet provider knows which IP address was asseigned to a specific person at a given date and time, and he will not disclose this information without good reason.
A hostname or domain may resolve to more than one IP address, which is commonly used for load sharing and redundancy. IP CHecker shows all alternative IP-Addresses in the DNS Records section. The IP Address section uses only one of these IP address, with each consecutive check cycling through all the IP addresses in a round robin manner.