In the United States, the user of a trademark can acquire enforceable trademark rights simply by using the mark in connection with goods and services. However, federal registration of the mark gives the owner valuable rights for enforcing the mark against unlawful users.
State registration often provides other substantive rights and should be considered along with federal registration.
A trademark, or "mark," is "a word, phrase, symbol or design, or a combination of words, phrases, symbols or designs, that identifies and distinguishes the source of the goods of one party from those of others."
Trademarks are used in connection with goods. Trademarks used in connection with services are often called service marks.