access time

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The time required for a computer program or device to locate and retrieve, or to write and store, a piece of data.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun computing The time interval between the issuing of a request to read data from or write data to a storage device and the completion of this action.
• noun computing An item of metadata indicating when a file was last accessed.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun (computer science) the interval between the time data is requested by the system and the time the data is provided by the drive