A trademark can be any "thing," such as a word, name, symbol, sound, color, packaging scheme or other device, or any combination thereof, as long as that "thing" is used to identify goods or services of one company and distinguish them from the goods or services of another.  Thus a trademark is a source-identifyer, and communicates to consumers that all products bearing a particular mark are from the same source.   Consumers need not know the exact manufacturer or service provider, but must believe the goods or services bearing the mark are not from the same source as those bearing a different mark.  For example, BETTY CROCKER receives trademark protection, even if nobody knew that the source of Betty Crocker products was actually General Mills, Inc., the company that owns the BETTY CROCKER trademark.

In order to qualify as a trademark, the mark must not be forbidden, must be distinctive, and must be used in commerce.  In a nutshell, the mark cannot consist of objectionable material, must be recognizable as a brand, and must have an effect upon sales.  For federal registration, those sales must be interstate sales.

Trademarks are often confused with trade names, which can be, but are not necessarily, trademarks.  Service markscollective marks andcertification marks are also distinguishable from trademarks.  However, it is not uncommon for the word "trademark" to refer to all such marks.  Finally, when used in some contexts, the word "trademark" refers specifically to a mark used to sell goods, as opposed to a service mark, which is a mark used to sell services.