Distinctiveness

The four levels of distinctiveness (by strength):

1.  Generic:  Not protected.  The general name as to which something is called (identifies the product).  No amount of money or proof or secondary meaning can make it a valid trademark.
Examples of common words that were once trademarks:  escalator, yo-yo

2.  Descriptive:  Can be protected if secondary meaning is proved.  Conveys an immediate idea of the ingredients, qualities, or characteristics of the goods (describes the product).

3.  Suggestive:  Entitled to registration with little to no proof of secondary meaning.  Requires imagination, thought and perception to reach a conclusion as to the nature of the goods.  It still needs to be explained.
Examples:  Orange Crush for soft drink, Playboy for skin mag

4.  Arbitrary/Fanciful:  Always protected without any proof of secondary meaning (i.e. Kodak, Pepsi).  No obvious connection between product/service and the mark.  Arbitrary is taking a word in usage and applying to products which have no relation (i.e. Apple for computers).  Fanciful is creating a word which had never existed before (i.e. Kodak or Pepsi).