A joint trademark refers to several similar trademarks registered by a registrant on the same commodity, including the original trademark and other joint trademarks. Its main purpose is to protect original trademarks and prevent others from insinuating and hitchhiking.

Pay attention to the difference between defensive trade mark and defensive trade mark. It refers to the trademark registered by the owner of a well-known trademark on different types of goods or services in order to prevent others from registering.