In general terms, the trademark laws of many countries define a "well-known" or "famous" trademark as the one which is known by those consumers belonging not only to the same markets, but also those ones related to the goods and services protected by the "well-known" trademark.
A well-known or famous trademark is the one which has gained recognition and reputation in the market, usually greatly due to the high quality of the goods or services as well as to large investments by its owner.
As a consequence, the famous trademark easily becomes known by the competition, thus increasing the risk of parasitism and misuse by third parties seeking to take advantage of this reputation to more easily introduce their products into the market.
In the case of well-known trademarks, the parasitic use by third parties seeking to take advantage of the reputation of the trademark, is enormous.
For this reason, this kind of trademarks should deserve a special protection, because of their high degree of exposure.
One of the requirements of the trademark laws of various countries is the compulsory use of the trademark for the goods and services for which it has been registered.
Thus, countries like Australia and some African countries, particularly those in which the requirement of use of the trademark applies, or where the risk of infringement is higher, introduced the figure of the "defensive trademark", according to which the owner of a well-known trademark can register a "defensive trademark" for those goods and services which they have no plans to use, but which nevertheless, may run the risk of being used by third parties in order to take advantage of the trademark awareness.
Under this protective figure of "defensive trademark", the owner of a well-known trademark may never use it for those goods or services, but without that being vulnerable to cancellation for lack of use.
That is, the "defensive trademark" is a trademark registered not exactly to be used, but only to create a scope of protection to the “well-known trademark”, in order to prevent it from possible infringement actions.
It can thus be said that the "defensive registration" is used to "shield" the well-known trademark, giving a broader protection than the regular registration, which is subject to attack for lack of use.