Trademark is any unique expression related to a product or service that distinguishes it from others. This expression could be a word, slogan, photograph, logo, graphic, colour combination, sound or even smell; however, most businesses are only looking for a brand name registration or logo registration. Owners of trademarks have exclusive rights to their use under the categories they are registered in (there are a total of 45 categories, called classes).
Trademark registration enables owners to easily establish their right to the trademark in court and earn royalties.
It also deters piracy and prevents similar company names from being registered by other businesses. You can conduct a trademark search, to check if your brand name clashes with existing trademarks. In India, you could get a ™ within three days, but it takes up to two years for it to be registered so that you can use the ® symbol.