In Python, a lambda function is a concise way to create anonymous functions. Lambda functions are defined using the lambda keyword, followed by the function parameters and the expression to be evaluated. They are particularly useful for short, one-time operations.

Example:

        
# Regular function
def add(x, y):
    return x + y

# Equivalent lambda function
add_lambda = lambda x, y: x + y
        
    

In the example above, add is a regular function that adds two numbers, and add_lambda is the equivalent lambda function. Lambda functions are often used when a small function is needed for a short period and doesn't require a separate named function.