According to Merriam-Webster, “expedited” means fast. But in the IRB world, “expedited” means that the research project presents not more than minimal risk and does not have to be reviewed by a Full IRB Committee. A list of categories of research that are eligible for an “expedited” review can be found on the OHRP Website.
Any “minor change” to previously-approved research may also be eligible for an expedited review, such as recruitment materials, some site amendments, and administrative changes. Generally, non-scientific submissions that do not change the risk/benefit ratio are considered minor changes.