From Longman Business Dictionary
trademarktrade-mark /ˈtreɪdmɑːk-mɑːrk/ abbreviation TM noun [countableC]COMMERCELAW a name, sign, or design used on a product to show it is made by a particular companyThe letters “WWF” are a registered trademark and must not be used without permission.
Trademarks and patents (=the sole right to make or sell a new invention, product, or method of doing something) can be referred to as industrial property, and the law stops them being used by any other company or person. They have to be registered (=put on an official list) at the Patent Office in the UK or at the Patent and Trademark Office in the US, and the owner of a patent must pay a renewal fee every year in order for it to continue.