Written Chinese
Because the majority of modern Chinese words contain more than one character, there are at least two measuring sticks for Chinese literacy: the number of characters known, and the number of words known. John DeFrancis, in the introduction to his "Advanced Chinese Reader", estimates that a typical Chinese college graduate recognizes 4,000 to 5,000 characters, and 40,000 to 60,000 words. Jerry Norman, in "Chinese", places the number of characters somewhat lower, at 3,000 to 4,000. These counts are complicated by the tangled development of Chinese characters. In many cases, a single character came to be written in multiple ways. This development was restrained to an extent by the standardization of the seal script during the Qin dynasty, but soon started again. Although the "Shuowen Jiezi" lists 10,516 characters—9,353 of them unique (some of which may already have been out of use by the time it was compiled) plus 1,163 graphic variants—the "Jiyun" of the Northern Song Dynasty, compiled less than a thousand years later in 1039, contains 53,525 characters, most of them graphic variants.
Chinese dictionary
The second system of dictionary organization is by recurring graphic components or radicals. The famous 100–121 CE "Shuowen Jiezi" (說文解字 "Explaining Simple and Analyzing Compound Characters") arranged characters through a system of 540 "bushou" (部首 "section header") radicals. The 543 CE "Yupian" (玉篇 "Jade Chapters"), from the Liang Dynasty, rearranged them into 542. The 1615 CE "Zihui" (字彙 "Character Glossary"), edited by Mei Yingzuo (梅膺祚) during the Ming Dynasty, simplified the 540 "Shuowen Jiezi" radicals to 214. It also originated the "radical-stroke" scheme of ordering characters on the number of residual graphic strokes besides the radical. The 1627 "Zhengzitong" (正字通 "Correct Character Mastery") also used 214. The 1716 CE "Kangxi Zidian" (康熙字典 "Kangxi Dictionary"), compiled under the Kangxi Emperor of the Qing Dynasty, became the standard dictionary for Chinese characters, and popularized the system of 214 radicals. As most Chinese characters are semantic-phonetic ones (形聲字), the radical method is usually effective, thus it continues to be widely used in the present day. However, sometimes the radical of a character is not obvious. To compensate this, a "Chart of Characters that Are Difficult to Look up" (難檢字表), arranged by the number of strokes of the characters, is usually provided.