Block

Declaration
...
Declaration
BEGIN
  Statement
  ...
  Statement
END

A block is a simple grouping of statements into one logical statement. You shouldn't need to use the block statement that often, as loops and if-then-else statements can contain multiple statements already. Most of the time, you may need to start a new block because you would like to introduce a new variable, such as:

VAR b := FALSE;
    x := 0;
BEGIN (* block *)
  WHILE NOT b DO 
    INC(x);
    b := (x > 5);
  END (* while *)
END (* block *)

Note that you can also use the WITH statement for creating new name bindings, also.