Definition   ITERATION is the act of repeating a construct,  or a slight variation on a construct again and again in some controlled fashion.

Definition   a WHILE statement is a repetition construct in which the item that is to be repeated is done so until a condition is met or true.

Definition   A COUNTER CONTROL LOOP is a repetition construct which is characterized by a priori (beforehand) knowledge of how many times the instruction block is to be run.

Definition   a DATA CONTROL LOOP is a repetition construct which is governed by ``metadata'' accompanying the data being processed.

Definition   INCREMENTAL PROGRAMMING is a programming methodology wherein one develops a program by writing a sequence of programs with the following properties:

1. The first program in the sequence performs some essentially trivial task,  but one which is fundamental to completion of the ultimate task.
   
2. The last program in the sequence performs the task of ultimate interest.
   
3. Each successor program performs a task only marginally more elaborate than its predecessor.