A named series of statements that performs some useful operation is referred to as a function.

Functions sometimes can take or don't take arguments. Similarily, they can generate or don't provide a result.

function definition: A statement that specifies the name, parameters, and statements that make up a new function.

A value formed by a function definition is referred to as a function object. The function's name is a variable that points to a function object.

The first line of a function definition is called the header.

The sequence of statements within a function definition is referred to as the body.

Parameter: A name given to the value delivered as an argument in a function.

A Statement that performs a function is referred to as a function call. The function name is followed by a list of arguments in parentheses.

When a function is called, it is given a value as an argument. This value is assigned to the function's appropriate parameter.

A variable defined within a function is referred to as a local variable. A local variable can only be used within the function in which it was created.

The outcome of a function is its return value. When a function call is used as an expression, the result is the expression's value.

A function that returns a value is called a fruitful function.

A function that always returns None is known as a void function.

None is a particular value that void functions return.

A module is a file that contains a group of related functions and definitions.

A statement that reads a module file and constructs a module object is known as an import statement.

A value formed by an import statement that allows access to the values defined in a module is referred to as a module object.

The syntax for invoking a function in another module by supplying the module name, a dot (period), and the function name in dot notation.

Using an expression as part of a larger expression or a statement as part of a larger statement is known as composition.

The sequence in which the statements are executed is called the execution flow.