function: A named sequence of statements that performs some useful operation. Functions may or may not take arguments and may or may not produce a result.
function deﬁnition: A statement that creates a new function, specifying its name, parameters, and the statements it executes.
function object: A value created by a function deﬁnition. The name of the function is a variable that refers to a function object.
header: The ﬁrst line of a function deﬁnition.
body: The sequence of statements inside a function deﬁnition.
parameter: A name used inside a function to refer to the value passed as an argument.
function call: A statement that executes a function. It consists of the function name followed by an argument list.
argument: A value provided to a function when the function is called. This value is assigned to the corresponding parameter in the function.
local variable: A variable deﬁned inside a function. A local variable can only be used inside its function.
return value: The result of a function. If a function call is used as an expression, the return value is the value of the expression.
fruitful function: A function that returns a value.
void function: A function that doesn’t return a value.
module: A ﬁle that contains a collection of related functions and other deﬁnitions.
import statement: A statement that reads a module ﬁle and creates a module object.
module object: A value created by an import statement that provides access to the values deﬁned in a module.
dot notation: The syntax for calling a function in another module by specifying the module name followed by a dot (period) and the function name.
composition: Using an expression as part of a larger expression, or a statement as part of a larger statement.
ﬂow of execution: The order in which statements are executed during a program run.
stack diagram: A graphical representation of a stack of functions, their variables, and the values they refer to.
frame: A box in a stack diagram that represents a function call. It contains the local variables and parameters of the function.
traceback: A list of the functions that are executing, printed when an exception occurs.