Definition - What does Read/Write Head mean?
A read/write head is a specific physical part of a hard disk that is responsible for reading data from, and writing data to, the disk. Read/write heads are typically made up of a thin horizontal magnetic blade attached to an actuator arm. By changing the electrical polarity of bits on a magnetic disk, the read/write arm effectively records data to a disk drive.
Techopedia explains Read/Write Head
The read/write head reads from and writes to a round hard disk platter that is housed in the physical drive container. Unlike the disk platter, the actual read/write head is extremely small. In modern disks these parts are designed down to the nanoscale. Simpler read/write heads were eventually replaced with metal-in-gap (MIG) heads, and then by thin-film heads that use different manufacturing processes to create smaller equipment. These innovations were part of what led to greater storage capacity for hard disk drives. In addition to advanced design for read/write heads, modern data storage technologies also involve alternatives that work differently. For instance, solid-state data storage involves changes to electrical polarity that do not involve an actual disk arm and read/write head. In addition, there have been advances in new laser data transfer that use laser technology instead of the physical disk infrastructure that includes read/write heads and disk platters.