Slave
A slave may refer to any of the following:
1. A slave is a computer or peripheral device that operates under the control of another computer peripheral.
Because "master/slave" may be considered offensive, it's better to use "device0/device1," "primary/secondary," "leader/follower," or "primary/replica" in its place.
2. A slave setting found on a hard drive or CD (compact disc) drive, and adjusted using jumpers, as shown below. The slave setting sets a drive as secondary and allows two devices to be attached to a single IDE/ATAPI connection.
Today, the secondary setting has been replaced by cable select, which determines the drive by where it's connected on the IDE (integrated drive electronics) cable.
Because "slave" may be considered offensive, it's better to refer to this drive as "secondary" or "device1."