One word. Trademark. It is a distinctive sign of some kind which is used by a business to uniquely identify itself and its products and services to consumers, and to distinguish the business and its products or services from those of other businesses. It prevents unauthorized use of a mark in relation to products or services outside its range.

If Apple does go with the name iPhone, it may have to deal with the internet phone company iPhone. The company offers a Voice Over IP service and has been doing so since 2003. However, the twist is that, Apple has registered for the iPhone trademark way back in 2002.

The way it works is that, if, the respective marks or products or services are not identical, similarity will generally be assessed by reference to whether there is a likelihood of confusion. Say, will consumers believe the products or services originated from the trademark owner even if didn't? If the respective marks and products or services are entirely dissimilar, trademark infringement may still be established.

Let me leave you with this thought: Is there a trademark dilution looming in the horizon?