# Glossary¶

argument
A value provided to a function when the function is called. This value is assigned to the corresponding parameter in the function. The argument can be the result of an expression which may involve operators, operands and calls to other fruitful functions.
body
The second part of a compound statement. The body consists of a sequence of statements all indented the same amount from the beginning of the header. The standard amount of indentation used within the Python community is 4 spaces.
calling stack
A sequence (stack) of frames, showing all the function calls that are in process but not yet complete. When one function’s code invokes another function call, there will be more than one frame on the stack.
compound statement

A statement that consists of two parts:

1. header - which begins with a keyword determining the statement type, and ends with a colon.
2. body - containing one or more statements indented the same amount from the header.

The syntax of a compound statement looks like this:

keyword expression:
statement
statement
...

docstring
If the first thing in a function body is a string (or, we’ll see later, in other situations too) that is attached to the function as its __doc__ attribute.
flow of execution
The order in which statements are executed during a program run.
function
A named sequence of statements that performs some useful operation. Functions may or may not take parameters and may or may not produce a result.
function call
A statement that executes a function. It consists of the name of the function followed by a list of arguments enclosed in parentheses.
function composition
Using the output from one function call as the input to another.
function definition
A statement that creates a new function, specifying its name, parameters, and the statements it executes.
fruitful function
A function that returns a value when it is called.
global variable
A variable defined at the top level, not inside any function.
The first part of a compound statement. A header line begins with a keyword and ends with a colon (:)
A special kind of function that is invoked on objects of particular types of objects, using the syntax <expr>.<methodname>(<additional parameter values>)