Generally speaking, a trademark is something you use to identify and distinguish your business or products. It can be a word or words, an image (ie: logo), or even a sound or smell. If a mark represents a product, it is a “trademark.” If it represents a service your provide, it is a “service mark.” However, the word “trademark” is used as a general term for both products and services.
Here is the legal definition from the federal law itself:
[section background_image=”” text_color=”#424242″ background_color=”#ffffff”]The term “trademark” includes any word, name, symbol, or device, or any combination thereof—
15 U.S. Code § 1127