Mazumas were a form of currency.
History
By the 82nd century, Mazumas were the main form of currency across much of the galaxy. (DWM: The Shape Shifter)
They were in use in on the planet Olleril in 5597. (NA: Tragedy Day)
Mazumas could be found in the form of coins, available in denominations including one and twenty (BFA: The Maltese Penguin) as well as banknotes called "Universal Credits." (DWM: The Shape Shifter)
The Doctor and Frobisher stole 250'000 Mazumas from Intra-Venus, Inc. (DWM: The Shape Shifter) They gave them to Ivan Asimoff for the Zyglot trust. (DWM: Polly the Glot)
Frobisher leant Jokk mazumas to take the shuttle. (DWM: Where Nobody Knows Your Name)
Behind the scenes
"Mazuma" is a Yiddish slang term for money, chiefly used in the United States.