A message call refers to a transaction where one smart contract interacts with another smart contract on a blockchain. This interaction can involve sending data or executing functions within the receiving contract.In a message call, the calling contract sends a transaction with specific information, such as the function to be executed and any necessary parameters. The receiving contract processes this message, which can lead to various outcomes, such as updating its state or transferring assets.Message calls are essential for creating complex decentralized applications (dApps) that rely on multiple contracts working together. For example, a decentralized finance (DeFi) platform may involve numerous smart contracts coordinating to facilitate lending, borrowing, and trading activities.Overall, message calls enable the intricate interactions that make programmable transactions and automated workflows possible on the blockchain. They enhance the functionality of smart contracts and contribute to the development of more robust and versatile applications.