Virtual currency, digital currency, and cryptocurrency
Virtual currency, digital currency, and cryptocurrency are tightly related terms. One way to think of them is like Russian nesting dolls. All cryptocurrencies can be found inside the virtual currency doll, and all virtual currency dolls are found within the digital currency doll.
In other words, all cryptocurrencies are virtual currencies, but not all virtual currencies are cryptocurrencies. Likewise, all virtual currencies are digital currencies, but not all digital currencies are virtual currencies.
Examples of virtual currencies that aren't cryptocurrencies include in-game currencies and frequent flyer miles. Examples of digital currencies that aren't virtual currencies include the U.S. dollars represented by my bank statement or any other fiat currency not held in physical form.