"A currency (from Middle English: curraunt, "in circulation", from Latin: currens, -entis), in the most specific sense is money in any form when in use or circulation as a medium of exchange, especially circulating banknotes and coins." [Emphasis added]

https://en.wikipedia.org/wiki/Money

"The money supply of a country consists of currency (banknotes and coins) and, depending on the particular definition used, one or more types of bank money..."

See also the caption on the first figure:

"A sample picture of a fictional ATM card. The largest part of the world's money exists only as accounting numbers which are transferred between financial computers. Various plastic cards and other devices give individual consumers the power to electronically transfer such money to and from their bank accounts, without the use of currency." [Emphasis added]

Also, are cryptocurrencies not currencies?

It's like the difference between "car" and "vehicle". Not all vehicles are cars. Not all money is currency. The boundary is not precise. Is an SUV a car? Maybe. Is a semi truck a car? Definitely not. But it's still a vehicle.

Is a dollar bill currency? Yes. Is the balance in your checking account currency? Maybe. Is a check currency? Definitely not. But it's still money.

> Also, are cryptocurrencies not currencies?

No. It's arguable whether or not they are money. The U.S. government treats them like a commodity for tax purposes.