return value: The result or output of a function if it contains a return statement (return keyword followed by a variable, expression, or value)
return statement: The line of code beginning with the return keyword, which terminates a function and returns its value.
dead code: Part of a program that can never run, possibly because it appears after a return statement.
None: Python keyword that indicates no value. This keyword is returned if a function does not feature a return statement.
initialization: An assignment that gives an initial value to a variable that will be updated, such as x = 0.
update: An assignment where the new value of the variable depends on the old, such as x = x + 1.
increment: An update that increases the value of a variable (often by one).
decrement: An update that decreases the value of a variable.