The term HIP-HOP'S MOS is an acronym for 'Masters of the Spoken Word', which is a title given to those who are considered to be the most influential and respected figures in the HIP-HOP music genre. These individuals are often credited with helping to shape the culture and sound of HIP-HOP, and are seen as pioneers in the industry. They are often credited with creating the unique sound and style of HIP-HOP that has become so popular today.