can refer to:
- the Chinese character 道 (Pinyin: dào; Wade-Giles: tao⁴), which is pronounced dō in Japanese and do (도) in Korean. It means "road," "way," "Daoism," "province," and "circuit."
- In Korea, Do is the designation for "province," as in Gyeonggi-do (경기도; 京畿道). See Provinces of Korea.
- In Japan, Dō means "circuit," when used in the name of Hokkaido (北海道) prefecture. See Prefectures of Japan.
- In Japan, the character also means "road," as in Tokaido (東海道) and Nakasendo (中山道).
- It is used as a suffix for various arts and implies that they are not just techniques but have spiritual elements. For example, Japanese tea ceremony is called "Sado" (茶道) and flower arrangement is called "Kado" (華道). Since the Meiji era, Japanese martial artists have adopted this suffix for names of martial arts such as Aikido, Judo and Kendo. This convention was introduced to Korea, but not to China, with martial arts themselves during the Japanese rule so that the suffix can be found in Taekwondo.
- the Chinese character 島 (Pinyin: dǎo; Wade-Giles: tao³), which is pronounced do in Korean and means "island". It used in the names of Korean islands (e.g., Ganghwa-do (강화도; 江華島), and Ulleung-do (울릉도; 鬱陵島). Note that "Jeju-do" transliterates two distinct Korean terms: "Jeju Province" (제주도; 濟州道) and "Jeju Island" (제주도; 濟州島).
- In solfege, do is the name of the first note of the scale.
- In English, do is a verb whose use as an auxiliary verb is often grammatically required for negation and for interrogative sentences.
- do is the ISO country code for the Dominican Republic.
- The Dornier (Do) aircraft.
- A nickname of Marshall Applewhite.
- Denominación de Origen, a Spanish appellation.