There are five actual categories of different types of trademarks, with one addition, and they all serve different purposes while keeping the same gist behind their existence: they are unique traits that define, represent, and symbolize the brand which has been developed or created it. The very fact that this trait exists is what sets the brand aside from the rest, giving it its own personality. For this reason is that it is so important to protect a trademark.

Here they are in simple terms:

• A fanciful mark (also called coined mark)- is very protected because it is a created term that becomes a household name with the brand. It is a new word in itself. Examples are Flickr, the photo app, Netflix, the movie site, and many others whose names are not in the dictionary. "Fanciful" refers to the coined or uniquely original nature of the mark.
• Arbitrary- another word that represents a brand name and has no connection to what the brand does or looks like. However, someone "arbitrarily" (because they felt like it) gave it that name. This is a very important mark to protect. Example: Cricket is a phone brand that has nothing to do with Crickets. Napster is a streaming site that is named after someone's cat. Apple is a computer brand, etc.
• Suggestive mark -is a trait that makes a brand unique based on what the consumer thinks that the brand does. It comes usually in the form of an action that is described by a name which puts an image in the mind of the consumer. For example, "TECHNICOLOR" is a suggestive mark used by the brand that gives (or used to give) color to movies and films. When you hear the word "technicolor" you automatically picture "something tech" giving color to a movie. It moves the imagination with the word.
• Descriptive marks- are hard to protect also because they are too obvious. For example, it is a very low chance for a cell phone company with a name such as "SellUlar" to get a way with getting protection by USPTO on the same grounds as Lektronics was not given protection for using a name that describes absolutely every other electronic brand of the same kind.
• Generic-this mark cannot be protected because of the general and universal characteristic of the word used for a promotion. For instance, product trade marks that are used so consistently and frequently that the trade mark comes to be identified with the generic category of the product, like Kleenex for "facial tissue" and "Band Aid" for elastic medical plaster.
• Secondary- this is a mark that represents a business but is used secondary to the one used the most. This is often done to tweak the brand according to current events. For instance, KFC is using the secondary mark of Kentucky GRILLED chicken only to promote their grilled chicken options. Yet, they are still Kentucky Fried.

As you can see the importance of protecting these creative, symbolic, and defining names is not always processable depending (in reality) in the uniqueness and creativity of the name. Hence, those seeking to be protected really need to come up with something very conceptual, new, and hard to replicate by others. This is when the USPTO approves the protection and the copyright is applied when is needed.