Trim and Moulding - what's the difference?

The term "trim and moulding" tend to be used interchangeably by contractors which makes understanding the differences confusing at times. What should I buy?

• Trim is the broad term describing the material used around doors and windows, floor to wall and ceiling to wall. Trim covers up the gaps. Example: between a floor and a wall.
• Moulding is the more decorative version of a piece of trim. It is used in the same places as trim achieving the same goals, however "elevated".

So, what should I buy? This all depends on budget and personal taste. In the end, the same purpose is achieved. To cover up gaps giving a clean finish to your living space.