Trademarks protect "signs" that can be used to indicate the origin of a service or goods, in the sense that people, usually consumers, would pick your service or goods over those of others because they associate that sign with a desired property of the service or goods. In most instances no objective quality need be attached to the service or goods as such. In other words, it is (only) because the consumer trusts in, or even just likes the sign, that he or she will choose your service or goods over others.
A trademark cannot be registered if the same or a similar trademark is already registered for the same or similar services or goods. In addition, if your trademark is similar to a famous trademark, you may be prevented from obtaining registration even though the famous trademark is not registered for the same or similar services or goods. You may use the trademark before applying to have it registered. However, the longer you delay applying for registration the greater the risk of someone else registering the same or a similar trademark for the same or similar services or goods.
Unfortunately, there is no easy measure to assess whether your trademark is similar to another trademark. The underlying principle is to protect consumers from confusing one trademark for another. The similarity is determined on a case by case basis, taking into account various aspects including the usual environment in which the consumer would make their decision. For example, in the case of a trademark for potato chips, which are typically bought in a quick decision while walking along a supermarket isle, an overall similarity may be sufficient to cause confusion, despite differences in detail. On the other hand, in the case of a trademark for yachts there may have to be a closer resemblance to cause confusion, since the consumer would usually spend more time considering the purchase of a yacht compared to buying potato chips.
One of the other requirements that needs to be met to obtain registration is that the trademark cannot be (too) descriptive of the service or goods. For example, trying to register the word "white" as a trademark for laundry detergents should not be successful since "white" describes a typical desired quality, i.e. making your whites white. Others should be free to refer to this quality when describing their own laundry detergents. Purely invented trademarks with no existing association to the service or goods appear the logical best choice, but in reality there is often a balance between a desired degree of descriptiveness, so as to infer a recognisable quality, and the need to be "non-descriptive enough".
The "signs" that can, in principle, be registered as trademarks have expanded well beyond the traditional notion of words and logo, to include a large variety of "signs" such as colour, smell, sound and 3-dimensional objects, to name but a few.
If you believe that you have created a "sign" that can make a consumer choose your service or goods over those of others simply because they like or recognise the sign, you should consider engaging a trade mark attorney (sometimes colloquially referred to as trademark lawyer or IP attorney) to discuss the process of applying for registration of your "sign" as a trademark.
NOTE: The information provided above does not constitute legal advise. If you do require legal advise, please contact us at firstname.lastname@example.org arrange a consultation.