ESATA stands for External SATA. It’s the SATA standard for external SATA devices.
If you need to plug in additional external storage devices, you can use an eSATA expansion card to add additional eSATA interfaces. You can then plug in additional eSATA drives.
ESATA has a max distances of 2 meters, max speed of 2.4 Gbps and uses an eSATA connector.