What is the abbreviation for megahertz?

The correct abbreviation for megahertz is represented as MHz. This notation follows the standard conventions for SI units, where 'M' denotes mega, which is a metric prefix meaning one million, and 'Hz' stands for hertz, the unit of frequency. The uppercase 'M' is essential as it indicates the megahertz unit specifically, distinguishing it from other values.

In the case of the other options, the variations such as 'mh' and 'Mhz' do not adhere to the correct casing rules for SI unit symbols. The lowercase 'm' does not represent mega and 'H' in lowercase is not recognized as hertz. The use of 'MH' lacks the 'z' entirely, which is a crucial part of the correct term. Therefore, it is important to use the uppercase 'M' and 'H' correctly, followed by the lowercase 'z' to accurately express megahertz as MHz.