Dilong (; lit. "earth dragon") is a Chinese dragon name that is also used to mean "earthworm" in traditional Chinese medicine and Geosaurus in zoological nomenclature.
In Chinese mythology, dilong Chinese: 地龍 "earth dragon" is one of many types of -long dragons such as shenlong Chinese: 神龍 "divine dragon" and huanglong Chinese: 黃龍 "Yellow Dragon". Since dì "earth; land; soil; ground" semantically contrasts with tian "heaven; sky" (e.g., tiandi Chinese: 天地 "heaven and earth; universe", see Tiandihui), the dilong is paired with the tianlong Chinese: 天龍 "heavenly dragon". Chinese dragons were supposedly able to fly, and thus were considered celestial creatures rather than terrestrial ones like the "earthbound" dilong. Two other exceptions are panlong Chinese: 蟠龍 "coiled/curled dragon; a dragon that has not ascended to heaven" and tulong Chinese: 土龍 "soil/earth dragon", which refers to the tuo "Chinese Alligator" (cf. Japanese mogura "mole").
Dilong first occurs in the mid-7th century CE History of the Southern Dynasties biography of Liang dynasty Admiral Wang Sengbian Chinese: 王僧辯 (d. 555 CE). It says witnesses saw lianglong Chinese: 兩龍 "two/paired dragons" that ascended into the sky, and this dilong "earth dragon" leaving Liang territory was interpreted as a portent of their defeat in 550 CE. Ronan and Needham cite another context in Wang's biography that says his boat had shuanglong Chinese: 雙龍 "two dragons" on the side, which they construe as a "literary emendation" for shuanglun Chinese: 雙輪 "two wheels" describing an early paddleboat.
Dilong or dilongzi Chinese: 地龍子 "earth dragon child" is an elegant name for the "earthworm; worm", which is usually called qiuyin . "Long Chinese: 龍 is employed in Chinese zoological nomenclature in much the same way that English dragon is used in dragonfly or dragonfish". First, "long names lifeforms thought to resemble dragons" (e.g., hailong Chinese: 海龍 "sea dragon" "sea otter; pipefish" or longluozi Chinese: 龍落子 "dragon fall child" "seahorse"); second, "long Chinese: 龍 is closely associated with dinosaurs" (e.g., oracle bones were originally called longgu Chinese: 龍骨 "dragon/dinosaur bones").
Dilong first means "earthworm" in the Qixiu Leigao Chinese: 七修類稿 written by the Ming dynasty scholar Lang Ying Chinese: 郎瑛 (1487–1566 CE). The 1578 Bencao Gangmu pharmacological entry for qiuyin Chinese: 蚯蚓 "earthworm" lists alternate names of dilong and tulong Chinese: 土龍 (see above). Li Shizhen notes these names derive from the myth that earthworms (like dragons) can create yinqing Chinese: 陰晴 "cloudy and clear; unsettled weather".
Dilongsan Chinese: 地龍散 "earth dragon powder", or Di Long, is used in traditional Chinese medicine. It is prepared from the abdomen of the Red earthworm, Lumbricus rubellus, and has many purported medicinal uses.
Dilong Chinese: 地龍 "earth dragon" is the modern Chinese term for the Mesozoic crocodilian Geosaurus (from Greek "earth lizard"). Contrast the feathered tyrannosaurid Dilong paradoxus that was named from Chinese dilong Chinese: 帝龍 "emperor dragon".
Chinese dilong or Japanese chiryū Chinese: 地龍 is the name of a chess piece in shogi. In Taikyoku shogi, this piece has Chinese: 地龍 "earth dragon" written on one side and yulong or uryū Chinese: 雨龍 "rain dragon" on the obverse.
One variety of Ditangquan martial arts is called Shaolin dilongquan Chinese: 少林地龙拳 "Shaolin Earth Dragon Boxing".
In the sexagenary cycle and Chinese astrology, duchen Chinese: 土辰 "The Year of the Earth Dragon" is a recurring combination of Dragon with the Five Elements/Phases, see Chinese calendar correspondence table and Tibetan calendar.
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