The full form of SCSI is: SMALL COMPUTER SYSTEM INTERFACE
What is SCSI in terms of computers?
SCSI refers to a standard interface which describes standards to be used while connecting peripheral or transferring data using them to computer(s).
This standard consists of commands for optical, electrical, logical, logical interfaces etc.
It is generally used with hard drives and servers. This standard is developed by American National Standards Institute (ANSI). SCSI is often called Parallel SCSI too.