In Elixir, `send` is used to send messages to a process, while `receive` is used to handle incoming messages. This enables asynchronous communication between processes.

In Elixir, the concepts of send and receive are fundamental to process communication and are essential for building concurrent applications. The send function is used to send messages from one process to another, allowing asynchronous communication. When you call send(pid, message), you are dispatching a message to the process identified by pid, and the message will be queued for that process to handle. This operation does not block the sending process; it continues executing immediately after the message is sent. On the other hand, the receive construct is used within a process to handle incoming messages. When a process calls receive do ... end, it enters a waiting state until it receives a message. The pattern inside the receive block defines how to match and handle messages. For example, you can specify different clauses to match different types of messages, allowing for versatile message handling logic. It's important to note that receive will only process messages that match its pattern; if no matching message is found, the process will remain in a waiting state. This asynchronous message passing model is at the heart of Elixir's concurrency model, enabling developers to build highly responsive and scalable applications that leverage lightweight processes for parallel execution.