In Python, a lambda function is a small, anonymous function defined using the lambda keyword. Unlike regular functions that are defined using the def keyword and can have multiple statements, lambda functions are limited to a single expression. This makes them particularly useful for short, one-time use cases where a full function definition would be unnecessarily verbose.

The syntax for a lambda function is straightforward: it starts with the lambda keyword, followed by the function’s arguments, a colon, and then the expression to be evaluated. For example, a simple lambda function that adds two numbers can be defined as add = lambda x, y: x + y. This function can then be called like any other function.

Lambda functions are often used in conjunction with functions like map(), filter(), and reduce(), allowing for concise and readable code when performing operations on collections of data ²³⁴.