• variable : a name that refers to a value.
  • assignment : a statement that assign a value to a variable.

  • state diagram : a graphical representation of a set of variables and the values they refer to.

  • keyword : a reserved word that is used to parse a program; you cannot use keywords like if, def and while as variable names.
  • operand : one of the values on which an operator operates.
  • expression : a combinations of variables, operators and values that represents a single result.
  • evaluate : to simplify an expression by performing the operations in order yo yield a single value.
  • statement : a section of code that represents a command or a action. So far, the statements we have seen are assignments or prints.
  • execute : to run a statement and do what it says.
  • interative mode : a way of using the Python interpreter by typing code at the prompt.
  • script mode : a way of using the Python interpreter to read code from a script and run it.
  • script : a program stored in a file.
  • order of operations : rules governing the order in which expressions involving multiple operators and operands are evaluated.
  • concatenate : to join two operands end-to-end.
  • comment : information in a program that is meant for other programmers (or anyone reading the source code) and has no effect on the execution of the program.
  • sintax error : an error in a program that make it impossible to parse (and therefore impossible to interpret)
  • exception : an error that is detected while the program is running
  • semantics : the meaning of a program.
  • semantic error : an error in a program that makes it do something other than the programmer intented.