How could I determine whether a descriptive mark can be trademarked?

For descriptive marks, US law draws a line between marks that are "merely descriptive" (not registrable) and ones that have or have developed a "secondary meaning" (are registrable). Secondary meaning is when customers associate the words with a particular company. This can be developed through long periods of sales, lots of advertising, substantial publicity, etc. Evidence of secondary meaning can be articles written by third parties that use the brand to mean the company and not to mean merely what the words mean, results of customer surveys, etc.

Whole seminars are conducted on what constitutes a valid trade or service mark. Check the USPTO web site for more details. You can also do searches for mark applications and registrations on the site which will give you a better idea of what has been accepted and rejected in the past. Generally a mark that is merely descriptive is not acceptable but there are exceptions.

You really can't tell until you seek to register the mark - if it is truly descriptive. If your mark is truly descriptive it could take years of use to make it a source identifier. If the mark is only suggestive - it can be registered, most likely on the Supplemental Register. Guide to Weak marks vs. Strong marks: A simple way to think about weak and strong marks is to picture a gauge that goes from cold (weak) to hot (strong): The coldest or weakest marks aren't even really marks at all. They are generic words that are incapable of identifying source. Think "BICYCLE" for "bicycles" or "MILK" for "a dairy-based beverage." These are common, everyday names for goods and services and are not registrable by themselves. Descriptive terms are warmer than generic terms, but are still very hard to protect. Descriptive terms directly tell you something about the goods and services and generally are not registrable without showing that a mark has, through long use, become a source identifier. Think "CREAMY" for "yogurt" or "THE ULTIMATE BIKE RACK" for "a bicycle rack." These words merely describe a feature or quality of the goods and services. Descriptive marks are harder to register and protect because they merely provide information about the goods and services. They don't "identify the source" of goods and services and "distinguish the source" of the goods and services from others. Moving along to suggestive marks, this is where things start to get warm. As the name implies, they "suggest" qualities or characteristics of the goods and services, without actually describing them. Think "QUICK N' NEAT" for "pie crust" or "GLANCE-A-DAY" for "calendars." Suggestive marks are registrable and are the next best thing to the hottest and strongest types of marks: "fanciful" marks and "arbitrary" marks. "Fanciful" and "arbitrary" marks are the easiest types of marks to protect because they are inherently distinctive and immediately function as source identifiers. They are typically creative or unusual, so it is less likely that other parties are using them for related goods and services. "Fanciful" marks are invented words with no dictionary or other known meaning. For example, "BELMICO" for "insurance services." "Arbitrary" marks are actual words with a known meaning, but words that have no association or relationship with the identified goods and services. For example, "BANANA" for "tires."

If you are only using the mark in one state, this is a matter of state law and you need to contact the Governor's Office or the Secretary of State of your state and determine whether or not the name that you want to use is available. However, if you want to engage in "interstate commerce" (more than one state), jurisdiction passes to the U.S. Trademark Office. There is a search engine online (TESS) that is available to the public that you can use to search different names and combinations of names. You will need to be patient and play with it for a while to learn how to use the search engine. There is a great deal of information there. Also, it is recommended that you seek the assistance of Counsel in selecting a name, since there are legal issues involved, and it is to your advantage to choose a strong name that can be registered and will withstand any legal challenge. You don't want to select a name and be in business for a few years, build up significant good-will, only to have to change your name because of legal issues. Good Luck!