The letters that constitute a trademark refer to the smallest writing unit of pinyin characters or phonetic symbols, including pinyin characters, foreign letters such as English letters, Latin letters, etc. The original Trademark Law classified trademarks consisting only of letters into the category of word trademarks. However, the newly revised Trademark Law in 2001 regarded letters as one of the constituent elements of a trademark. This provision is more realistic and convenient for trademark supervisors. The department reviews and approves trademark registration applications in accordance with the law.