Proper noun
the Middle Stone Age
A period of African prehistory between the Early Stone Age and the Late Stone Age, generally considered to have begun around 280,000 years ago and ended around 50–25,000 years ago.
Synonym: (initialism) MSA
The presence of such eggshells with engraved hatched symbols dating from the Howiesons Poort period of the Middle Stone Age at Diepkloof Rock Shelter in South Africa suggests ostriches were an important part of human life as early as 60,000 BP. Source: Internet
Other evidence of religious ideas include symbolic artifacts from Middle Stone Age sites in Africa. Source: Internet
Therefore, care must be taken in translating "Mesolithic" as "Middle Stone Age", as the latter term has an unrelated technical meaning in the context of African archaeology. Source: Internet