In the context of cryptocurrencies and blockchain technology, the “main chain” refers to the primary blockchain in a system. This is the original chain where the cryptocurrency originated and is typically the one that holds the most value and has the highest level of security.
For instance, Bitcoin’s main chain is the Bitcoin blockchain, and Ethereum’s main chain is the Ethereum blockchain. These main chains have the highest amount of computational power backing them, and they also tend to be the ones with the largest number of transactions.
In addition, the term “main chain” can also be used in relation to sidechains and off-chain solutions. In this context, the main chain is the primary, secure blockchain, while the sidechains are ancillary blockchains that can be used to improve scalability and performance by handling certain transactions away from the main chain. Similarly, off-chain transactions are those that take place away from the main chain to alleviate congestion and improve speed. After their completion, these transactions are settled on the main chain.
Please note that the term “main chain” can also have a different meaning when discussing forks in the blockchain. In this case, the “main chain” is typically considered the longest chain, i.e., the one with the most proof-of-work behind it, while shorter chains resulting from forks are usually considered “orphan” or “stale” blocks.