Your internet service provider (ISP) provides you an IP address. This advertises your computer to the internet.
An IP address is like your home postal address, which is a piece in a larger city block. A city block, in internet language, is a network prefix. To go one step further, network prefixes are part of autonomous systems (AS). When connecting people to the internet, ISPs will assign an IP address to your computer.
The IP address that is assigned to you is most likely a dynamic IP address. This is the most common for residential customers. This means that the IP address changes frequently, which provides customers and ISPs cost savings. In the case of Germany, Deutsche Telekom is typically changing IP addresses every day.
The alternative to this system is the static IP address. This is an IP address that never changes. If you are running a dynamic cloud environment, this would be necessary for advertising your content to the public internet. This is a primary function of AWS Elastic IPs, which contain the static IP address component.
A static IP is useful for various reasons. In cloud computing, a static IP address is advantageous for DNS queries. If IPs are changing, this can affect the content loading process.
Static IP addresses are IPs which do not change. They are common for business and cloud computing, which is why AWS includes this within the Elastic IP framework.