AirGap

AirGap refers to the practice of keeping private keys for cryptocurrencies completely offline, thus creating a high level of security. The private keys are stored on an air-gapped device, meaning it has never been connected to the internet, making it impervious to online hacks. This method is often used by people looking to secure large amounts of cryptocurrencies. 

A cryptocurrency investor could use a hardware wallet that is permanently kept offline (air-gapped) to store the private keys for their Bitcoin holdings. By doing so, they ensure that their funds are protected from cyberattacks, as there is no direct way to access the wallet from the internet.