The Erya () is the oldest extant Chinese lexicon. Bernhard Karlgren (1931: 49) concluded that "the major part of its glosses must reasonably date from" the 3rd century BC. Since the title, combining er ("you; your; adverbial suffix *") and ya ("proper; correct; refined; elegant"), literally means "your correctness," commentators interpret this er as a phonetic loan character for another er ( "near; close; approach"). According to W. South Coblin (1993: 94): "The interpretation of the title as something like 'approaching what is correct, proper, refined' is now widely accepted." It has been translated as "The Literary Expositor," "The Ready Rectifier" (both by James Legge), and "Progress Towards Correctness" (A. von Rosthorn).
The book's author is unknown. Although it is traditionally attributed to the Duke of Zhou, Confucius, or his disciples, scholarship suggests that someone compiled and edited diverse glosses from commentaries to pre-Qin texts, especially the Shijing. The Erya was considered the authoritative lexicographic guide to Chinese classic texts during the Han Dynasty, and it was officially categorised as one of the Thirteen Confucian Classics during the Song Dynasty. The best-known annotations to the book are the Erya zhu (; "Erya Commentary") by Guo Pu and the Erya shu (; "Erya Sub-commentary") by Xing Bing (; 931-1010).
The Erya has been described as a dictionary, glossary, synonymicon, thesaurus, and encyclopaedia. Karlgren (1931: 46) explains that the book "is not a dictionary in abstracto, it is a collection of direct glosses to concrete passages in ancient texts." The received text contains a total of about 11,000 words and 1,154 definitions. It is divided into nineteen sections, the first of which is subdivided into two parts. The title of each chapter combines shi ("explain; elucidate") with a term describing the words under definition. Seven chapters (4, 8, 9, 10, 12, 18, and 19) are organized into taxonomies. For instance, chapter 4 defines terms for: paternal clan (宗族), maternal relatives (母黨), wife's relatives (妻黨), and marriage (婚姻). The text is divided between the first three heterogeneous chapters defining abstract words and the last sixteen semantically-arranged chapters defining concrete words. The last seven – concerning grasses, trees, insects and reptiles, fish, birds, wild animals, and domestic animals – describe more than 590 kinds of flora and fauna. It is a valuable document of natural history and historical biogeography.
| Chapter | Chinese | Pinyin | Translation | Subject |
|---|---|---|---|---|
| 01 | 釋詁 | Shigu | Explaining Old Words | verbs, adjectives, adverbs, grammatical particles |
| 02 | 釋言 | Shiyan | Explaining Words | verbs, adjectives, adverbs |
| 03 | 釋訓 | Shixun | Explaining Instructions | adjectives, adverbs, mostly with reduplication |
| 04 | 釋親 | Shiqin | Explaining Relatives | kinship, marriage |
| 05 | 釋宮 | Shigong | Explaining Dwellings | architecture, engineering |
| 06 | 釋器 | Shiqi | Explaining Utensils | tools, weapons, clothing, and their uses |
| 07 | 釋樂 | Shiyue | Explaining Music | music, musical instruments, dancing |
| 08 | 釋天 | Shitian | Explaining Heaven | astronomy, astrology, meteorology, calendar |
| 09 | 釋地 | Shidi | Explaining Earth | geography, geology, some regional lore |
| 10 | 釋丘 | Shiqiu | Explaining Hills | topography, Fengshui terms |
| 11 | 釋山 | Shishan | Explaining Mountains | mountains, famous mountains |
| 12 | 釋水 | Shishui | Explaining Rivers | rivers, navigation, irrigation, boating |
| 13 | 釋草 | Shicao | Explaining Plants | grasses, herbs, grains, vegetables |
| 14 | 釋木 | Shimu | Explaining Trees | trees, shrubs, some botanical terms |
| 15 | 釋蟲 | Shichong | Explaining Insects | insects, spiders, reptiles, etc. |
| 16 | 釋魚 | Shiyu | Explaining Fishes | fish, amphibians, crustaceans, reptiles, etc. |
| 17 | 釋鳥 | Shiniao | Explaining Birds | wildfowl, ornithology |
| 18 | 釋獸 | Shishou | Explaining Beasts | wild animals, legendary animals |
| 19 | 釋畜 | Shichu | Explaining Domestic Animals | livestock, pets, poultry, some zoological terms |
In the history of Chinese lexicography, only a few dictionaries followed the Erya's arrangement by semantic categories like Heaven and Earth, for instance, the Guangya and Shiming. Nearly all Chinese dictionaries followed arrangements into systems of character radicals, first introduced in the Shuowen Jiezi. Chinese leishu (; "reference works arranged by categories; encyclopedias"), such as the Yongle Encyclopedia, were also semantically arranged.
Owing to its laconic lexicographical style, the Erya is the only Chinese classic that has not been fully translated into English. However, there are several unpublished PhD dissertations translating particular chapters.