Each Chinese character represents a monosyllabic Chinese word or morpheme. In 100 CE, the famed Han dynasty scholar Xu Shen classified characters into six categories, namely pictographs, simple ideographs, compound ideographs, phonetic loans, phonetic compounds and derivative characters. Of these, only 4% were categorized as pictographs, including many of the simplest characters, such as "rén" (human), "rì" (sun), "shān" (mountain; hill), "shuǐ" (water). Between 80% and 90% were classified as phonetic compounds such as "chōng" (pour), combining a phonetic component "zhōng" (middle) with a semantic radical (water). Almost all characters created since have been made using this format. The 18th-century Kangxi Dictionary recognized 214 radicals.