Blockchain (originally block chain) — a distributed ledger where storage devices aren't connected to a shared server. This ledger stores a constantly growing number of records, called blocks. Each block contains a timestamp and a link to the previous block.

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Cryptocurrencies are monetary units (also called "coins" or "tokens") encrypted using cryptographic technologies. These monetary units do not have a physical counterpart, they exist only in the virtual space. Tokens are protected from forgery, because they represent encrypted data which cannot be copied (the use of cryptography is the reason for the "crypto" prefix in the name).

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ICO or Initial Coin Offering — an instrument for raising funds where the future cryptocurrency is sold for existing, liquid virtual money. You transfer bitcoins or ETH (Ethereum) to the ICO, and instead you receive the tokens of the new project. This is another realization of the crowdfunding model, when participants finance the company development now in order to get from it something in the future.

Pre-ICO — is a stage preceding the ICO (the main stage) aimed at raising funds for the project. Pre-ICOs are usually held to gauge the demand for the project, as well as to evaluate and receive community support, expand the marketing budget before the main stage. Not every project holds a pre-ICO.