The term 'FUNDAMENTAL SOURCE' can be broken down into two words, 'FUNDAMENTAL' and 'SOURCE'. The word 'FUNDAMENTAL' is defined as something that is essential or basic, while the word 'SOURCE' is defined as the origin or beginning of something. Therefore, the term 'FUNDAMENTAL SOURCE' can be interpreted as the essential origin or beginning of something. This could refer to a variety of things, such as the origin of a particular idea, the SOURCE of a particular event, or the basis of a particular belief.