Google's effort to register the word 'Glass' as a trademark for its wearable electronic glasses has been stalled by the United States' Trademark Office.

While Google has already registered the term 'Google Glass' as a trademark, a report in the Wall Street Journal this week revealed that the U.S. Patent and Trademark Office has objected to the 'Glass' trademark application, submitted last year.

According to the report, a trademark examiner raised two objections, one of which was that the trademark was too similar to other trademarks containing the word 'glass', which could lead to confusion for consumers.

The other objection was that the word 'glass' was merely descriptive. Such generic terms cannot be trademarked under US federal law.

According to The Wall Street Journal, Google's trademark attorneys wrote a 1,928-page letter to the government in response to the Trademark Office's decision to stall the trademark application.

The letter from Google's lawyers contained around 1,900 articles about Google Glass, with the remainder of the letter disputing the trademark examiner’s objection that using the word 'glass' as a trademark would confuse consumers and the assertion that it was merely a descriptive word.

Although Google is not required to trademark the word in order to use it for its glasses device, if the company is not to able to register ‘Glass’ as a trademark, it will make it much harder to counter trademark infringements.

The Trademark Office has yet to make a final ruling on the application.

The trademark registration roadblock comes as the company pays out a €1 million fine relating to privacy breaches in Italy, according to the country's privacy watchdog.

The fine was issued after the company came under fire in 2010 over its street-mapping service. It used unmarked cars to collect digital images, meaning that bystanders were not able to ascertain whether they were being filmed or the identity of the organisation carrying out the recording.

At the time, Italian authorities asked Google to apply stickers to its cars and to publicise its movements three days in advance on radio stations and in local newspapers.

Although the company complied with the requests, the watchdog ruled that Google had to pay a fine for "the illicit collection of data destined for a large database of particular significance."