also known as rotational delay. The time taken for a disc to rotate from the current position (on the required track) to the position containing the first required data block.

(computer science) the time it takes for a specific block of data on a data track to rotate around to the read/write head

The amount of delay in obtaining information from a disk due to the rotation of the disk. For a disk rotating at 5200 RPM, the average rotational latency is 5.8 milliseconds. See also Mechanical Latency.

The delay time from when a disk drive's read/write head is on-track and when the requested data rotates under it.

The time it takes for the desired disk sector to be put into position under the read/write head, which must be done before data can be read from or written to the disk. For example, 5,400 RPM disks take II, 1ms to complete a full revolution and the average latency is 5.56 ms.