An initial coin offering (ICO) or initial currency offering is a type of funding using cryptocurrencies. 

In an ICO, a quantity of cryptocurrency is sold in the form of "tokens" ("coins") to speculators, in exchange for legal tender or other cryptocurrencies such as Bitcoin or Ethereum. The tokens sold are promoted as future functional units of currency if or when the ICO's funding goal is met and the project launches. In some cases like Ethereum, the tokens are required to use the system for its purposes.