Chinese dictionary in the context of Erya

A radical (Chinese: 部首; pinyin: bùshǒu; lit. 'section header'), or indexing component, is a visually prominent component of a Chinese character under which the character is traditionally listed in a Chinese dictionary. The radical for a character is typically a semantic component, but it can also be another structural component or an artificially extracted portion of the character. In some cases, the original semantic or phonological connection has become obscure, owing to changes in the meaning or pronunciation of the character over time.

The use of the English term radical is based on an analogy between the structure of Chinese characters and the inflection of words in European languages. Radicals are also sometimes called classifiers, but this name is more commonly applied to the grammatical measure words in Chinese.

A Chinese–English Dictionary (1892), compiled by the British consular officer and sinologist Herbert Allen Giles (1845–1935), is the first Chinese–English encyclopedic dictionary. Giles started compilation after being rebuked for criticizing mistranslations in Samuel Wells Williams' (1874) A Syllabic Dictionary of the Chinese Language. The 1,461-page first edition contains 13,848 Chinese character head entries alphabetically collated by Beijing Mandarin pronunciation romanized in the Wade–Giles system, which Giles created as a modification of Thomas Wade's (1867) system. Giles' dictionary furthermore gives pronunciations from nine regional varieties of Chinese, and three Sino-Xenic languages Japanese, Korean, and Vietnamese. Giles revised his dictionary into the 1,813-page second edition (1912) with the addition of 67 entries and numerous usage examples.

The Kangxi Dictionary (Chinese: 康熙字典; pinyin: Kāngxī zìdiǎn) is a Chinese dictionary published in 1716 during the High Qing, considered from the time of its publishing until the early 20th century to be the most authoritative reference for written Chinese characters. Wanting an improvement upon earlier dictionaries, as well as to show his concern for Confucian culture and to foster standardization of the Chinese writing system, its compilation was ordered by the Kangxi Emperor in 1710, from whom the compendium gets its name. The dictionary was the largest of its kind, containing 47,043 character entries. Around 40% of them were graphical variants, while others were dead, archaic, or found only once in the Classical Chinese corpus. In today's vernacular written Chinese, fewer than a quarter of the dictionary's characters are commonly used.

The text is available in many forms, from Qing dynasty block print editions, to reprints using traditional Chinese bookbinding, to Western-style hardcovers including revisions and ancillary essays, to a digitized version accessible via the internet.

Fanqie is a method used in traditional Chinese lexicography to indicate the pronunciation of a monosyllabic character by using two other characters, one with the same initial consonant as the desired syllable and one in which the rest of the syllable (the final) matches.The method was introduced in the 3rd century AD and is to some extent still used in commentaries on the classics and dictionaries.

The Yiqiejing yinyi (c. 649) is the oldest surviving Chinese dictionary of technical Buddhist terminology, and the archetype for later Chinese bilingual dictionaries. This specialized glossary was compiled by the Tang dynasty lexicographer and monk Xuanying (玄應), who was a translator for the famous pilgrim and Sanskritist monk Xuanzang. When Xuanying died he had only finished 25 chapters of the dictionary, but in 807 another Tang monk named Huilin (慧琳) compiled an enlarged 100-chapter version bearing the same title.

The Fangyan is a Chinese dictionary compiled in the early 1st century CE by the poet and philosopher Yang Xiong (53 BCE – 18 CE). It was the first Chinese dictionary to include significant regional vocabulary, and is considered the "most significant lexicographic work" of its era. His dictionary's preface explains how he spent 27 years amassing and collating the dictionary. Yang collected regionalisms from many sources, particularly the 'light carriage' (輶軒 yóuxuān) surveys made during the Zhou and Qin dynasties, where imperial emissaries were sent into the countryside annually to record folk songs and idioms from across China, reaching as far north as Korea.

The Ziyuan (Chinese: 字苑; pinyin: Zìyuàn; Wade–Giles: Tzu-yüan; lit. 'Character Garden'; or "Essays on Chinese Characters") was a Chinese dictionary attributed to the Eastern Jin Dynasty scholar Ge Hong. The original text was lost, and the small modern Ziyuan recension has 34 headwords, mostly Chinese Buddhist loanword terminology.

The Ziyuan is notable for having the first occurrence of the Chinese borrowing ta (塔; tǎ; t'a; "tower; pagoda"). Feng (2004:205) classifies ta as a "monosyllabic phonemic loanword," and notes:

The Cihai is a large-scale dictionary and encyclopedia of Standard Mandarin Chinese. The Zhonghua Book Company published the first Cihai edition in 1938, and the Shanghai Lexicographical Publishing House revised editions in 1979, 1989, 1999, and 2009. A standard bibliography of Chinese reference works calls the Cihai an "outstanding dictionary".

The Shuowen Jiezi is a Chinese dictionary compiled by Xu Shen c. 100 CE, during the Eastern Han dynasty (25–220 CE). While prefigured by earlier reference works for Chinese characters like the Erya (c. 3rd century BCE), the Shuowen Jiezi contains the first comprehensive analysis of characters in terms of their structure, where Xu attempted to provide rationales for their construction. It was also the first to organize its entries into sections according to shared components called radicals.