The core-mantle boundary refers to the interface between the Earth's solid inner core and the molten outer core. It is one of the most important parts of the planet, as it plays a crucial role in the dynamics of the Earth's magnetic field and geodynamic processes. The term "core-mantle boundary" is a commonly used scientific term, but there are also other synonyms that refer to this interface, such as the core-mantle interface, the D" layer, and the Gutenberg discontinuity. These terms are used interchangeably and are all integral to understanding the geological makeup of the Earth.