Off-chain transactions that take place may later be reported or bundled together before being sent to the main chain.
Pair
Exchange cryptocurrencies with each other, like the trading pair BTC/ETH.
Altcoin
Altcoin is the term given to describe alternative digital assets, such as a coin or token that is not Bitcoin. This nomenclature comes from the idea that Bitcoin is the original cryptocurrency and that all others are then considered “alternate” or “alternative” coins.
Coin
Cryptocurrencies known as coins run on separate blockchains and are unrelated to other coins. Such a cryptocurrency's single unit is also known as a coin.