1. Owning a lot of money and/or expensive property: The rich landlord owned extensive acreage of valuable farmland and he even had access to a river.
2. Worth a great deal of money: The local owner of a brewery left a richer endowment to the famous university than anyone had ever done before.
3. Made from or consisting of things of the highest quality: The furniture upholstery and drapery were made of the richest brocade fabric and colors that Kate had ever seen before.
4. Providing or having a large amount of something that is needed or wanted: This lexicon has a rich source of vocabulary information.
5. Very interesting and full of many different things: Carol and Virginia have a rich vocabulary which they strive to share with others.
6. Producing a big quantity of something: Novels have always been the rich contents of material for the movie industry.

These days, the internet is a very rich source of all kinds of information for everyone.

7. Etymology: the original meaning of rich was "mighty, noble".

It goes back ultimately to the Indo-European base reg-, "move in a straight line"; therefore, "direct" and "rule" which is the source of English right from Latin rex, "king" (ancestor of English regent, regiment, etc.).