According to Oxford Dictionary, a trademark is a symbol, word, or words legally registered or established by use as representing a company or product.
Functions of a trademark
A trademark has four functions, the primary one being it identifies the product and its origin, the second one is provision assurance of the its quality, the third one is the trademark acts as an advertisement for the product its on, and the last one being it creates a prominent image of the product or brand in the minds of current and prospective consumers of that products.
When a trademark becomes so popular or significant that it replaces the original term kept for that product, then it is known as trademark generalisation. This trademark becomes synonymous with the generic term for a product or a category of products, and hence the trademark owner loses the exclusive right of to use it.
For example, “Aspirin” was the trademarked name of a drug originally made by a German pharmaceutical company - Bayer AG, but after the term “Aspirin” gained more popularity than its medical term “acetylsalicylic acid”, aspirin suffered from trademark generalisation. Therefore, subsequently losing the trademark case over “Aspirin” in 1918 in the United States Supreme Court.
Trademark grants an exclusive use of a word to its owner, thus giving a monopoly to its owner. Meanwhile, trademark generalisation encourages competition as the sellers can now correctly describe the product they are selling and making it easily discoverable to the consumers due to the popularity of the trademark’s name.
[Jacqueline Stern p10] Granting exclusive use of a term that is the only publicly recognizable name for a category of goods unfairly limits competition because it confers a monopoly on the trademark owner by rendering competitors unable to describe their goods effectively. Competitors are hampered in the sale of their goods, and consumers cannot easily discover whether products similar to the trademarked goods are available from other sources.
[Ingram, p1] There are many names that were once trademarks that came to be used by the public as the descriptive name for the product. As I grew up as a child in the 1930s I had no idea that trampoline, yo-yo, brassiere, escalator, thermos, aspirin, and cellophane had once been registered trademarks. They were simply the names everyone used to describe those products. There were many other former trademarks that were already generic by then, or became such in more recent years.