Daikon (大根 (だいこん) or mooli (Raphanus sativus var. longipinnatus) is a mild-flavored winter radish usually characterized by fast-growing leaves and a long, white, napiform root. Native to continental East Asia, daikon is and its cultivars are now harvested and consumed globally. In some locations, daikon is left unharvested to loosen compacted soils and recover nutrients.

In culinary context, daikon (Japanese: 大根, lit. 'big root') or daikon radish is most common. Historical ties to South Asia give it the name mooli (Hindi: मूली, romanized: mūlī) in certain cultures. Other terms include white radish, winter radish, Oriental radish, and long white radish, while still other names can be used. Other synonyms usually vary by region or describe regional varieties of the vegetable. When it is necessary to distinguish the usual Japanese form from others, it is sometimes known as Japanese radish.

The vegetable's Chinese names are still uncommon in English. In most forms of Chinese cuisine, it is usually known as bái luóbo (white radish). Although in Cantonese and Malaysian cuisine, it is encountered as lobak or lo pak, which are Cantonese pronunciations of the general Chinese term for "radish" or "carrot" (蘿蔔). In the cuisines of Hokkien and Teochew-speaking areas such as Singapore, Thailand, and Taiwan, it is also known as chai tow or chai tau (菜頭). Any of these may be referred to as "radish," with the regional variety implied by context. In English-speaking countries, it is also sometimes marketed as icicle radish.^{[citation needed]}

In mainland China and Singapore, the calque white carrot or misnomer carrot is sometimes used, owing to the similarity of the vegetables' names in Mandarin and Hokkien. This variant inspired the title for a popular guidebook on Singaporean street food, There's No Carrot in Carrot Cake, which refers to chai tow kway, a kind of cake made from daikon.

In North America, it is primarily grown not for food but as a fallow crop, with the roots left unharvested to prevent soil compaction; the leaves (if harvested) are used as animal fodder. The official general name used by the United States Department of Agriculture is oilseed radish, but this is only used in non-culinary contexts. Other English terms employed when daikon is used as animal feed or as a soil ripper are "forage radish", "fodder radish", and "tillage radish".

In Hong Kong, the misnomer turnip is also used. This name lends its name to the dish "turnip cake".

Several nonwhite varieties occur. The Cantonese lobak, lo pak, etc., sometimes refer to the usual Chinese form but is also applied to a form of daikon with a light green coloration of the top area of the root around the leaves. The Korean radish, also called mu, has a similar pale green shade halfway down from the top and are generally shorter, stouter, and sturdier, with denser flesh and softer leaves. Both are often spicier than the long white radishes.^{[citation needed]}

The heirloom watermelon radish is another Chinese variety of daikon with a dull green exterior but a bright rose or fuchsia-colored center. Its Chinese name (t 心裡美蘿蔔, s 心里美萝卜, xīnlǐměi luóbó) is sometimes irregularly romanized as the shinrimei radish and sometimes translated as the "beauty heart," "beautiful heart inside," or "roseheart" radish.^{[citation needed]}