A Lambda function refers to a serverless computing feature provided by Amazon Web Services (AWS). AWS Lambda allows developers to run code in response to events without needing to provision or manage servers. It’s a part of the FaaS (Function as a Service) model, enabling users to write functions in various programming languages such as Python, Node.js, Java, and more, and deploy them on the AWS platform.

The key advantage of Lambda is that it automatically scales based on the request volume and only charges for the compute time consumed, which makes it a cost-efficient solution for applications with unpredictable or sporadic usage patterns. Lambda functions are triggered by events such as HTTP requests via API Gateway, file uploads to S3, or database changes in DynamoDB.

Lambda is often used for tasks like real-time data processing, event-driven automation, and backend services for mobile and web applications. Its serverless architecture eliminates the need for infrastructure management, allowing developers to focus on writing code while AWS handles scaling, patching, and maintenance.