In an unexpected twist, the United States Patent and Trademark Office (USPTO) officially denied Apple a trademark for the iPad Mini tablet.

What does this mean? Well, if the decision sticks Apple will ultimately have no choice but to rename its smaller tablet and apply for a trademark again. For now, however, the Cupertino giant still has the right to reply to the USPTO's of its trademark application and correct the issues reviewers pointed out.

According to the rejection letter recently uncovered by Patently Apple, the primary issue that stands at the core of this trademark denial is that the iPad Mini mark "merely describes a feature or characteristic of applicant's good." The USPTO takes into account the separate parts of the device's name, which in this case are "I," "pad," and "mini."

"In this case, both the individual components and the composite result are descriptive of applicant's goods and do not create a unique, incongruous, or non-descriptive meaning in relation to the goods being small handheld mobile devices comprising tablet computers capable of providing internet access," explains the rejection letter. "Therefore, the mark is merely descriptive of a feature or characteristic of the goods and registration is refused under Section 2(e)(1) of the Trademark Act."

To challenge the decision, Apple must somehow show the USPTO that "mini" is a distinctive name. Otherwise, the iMaker cannot "claim exclusive rights to terms or designs that others may need to use to describe or show their goods r services in the marketplace."

Moreover, the USPTO reviewer apparently also found an issue with Apple's submission of its iPad Mini product website page as a "specimen" for the trademark.

"It fails to include a picture or a sufficient textual description of the goods in sufficiently close proximity to the necessary ordering information/a weblink for ordering the goods," the letter further explains, referring to Apple's iPad Mini product page.

In other words, the USPTO sees that website product page as more of an advertisement, which cannot serve "to show trademark use in connection with goods." Instead, Apple will have to submit a substitute specimen that can show the mark in use commercially, for each class of goods the company specified in the trademark application.

Patently Apple only discovered this rejection letter recently, but Apple received it in late January 2013. Apple's army of lawyers surely made a stronger case for the iPad Mini's trademark since then.