In this case, it’s a webpage that gives away small amounts of NANO for free so you can test it yourself. This is only possible because of the no fees feature of NANO and the fact that it is highly divisible.

Most other cryptocurrencies require you to buy them before you can test them.

I know of two NANO faucets:

https://www.freenanofaucet.com/

https://nano-faucet.org/