A mebibyte is a unit of measure. It represents 1024 * 1024 bytes.
A mebibyte (a contraction of mega binary byte) is a unit of information or computer data storage, symbol MiB.
The mebibyte is closely related to the megabyte (MB). Megabyte can either be a synonym for mebibyte, or refer to 106 bytes = 1,000,000 bytes, depending on context (see binary prefix for background). The two numbers are relatively close together, but mistaking the two has nevertheless led to problems.