As defined in Italy:
In the United States, the National Pasta Association (which has no links with its Italian counterpart, the Unione Industriali Pastai Italiani) lists vermicelli as a thinner type of spaghetti.
The Code of Federal Regulations of the United States of America (Title 21, paragraph 16.2) defines "spaghetti" and "vermicelli" by diameter:
In 14th-century Italy, long pasta shapes had varying local names. Barnabas de Reatinis of Reggio notes in his Compendium de naturis et proprietatibus alimentorum (1338) that the Tuscan vermicelli are called orati in Bologna, minutelli in Venice, fermentini in Reggio, and pancardelle in Mantua.
The first mention of a vermicelli recipe is in the book De arte Coquinaria per vermicelli e maccaroni siciliani (The Art of Cooking Sicilian Macaroni and Vermicelli), compiled by the famous Maestro Martino da Como, unequalled in his field at the time and perhaps the first "celebrity chef," who was the chef at the Roman palazzo of the papal chamberlain ("camerlengo"), the Patriarch of Aquileia. In Martino's Libro de arte coquinaria, there are several recipes for vermicelli, which can last two or three years (doi o tre anni) when dried in the sun.
In English, the Italian loanword "vermicelli" is used to indicate different sorts of long pasta shapes from different parts of the world but mostly from South or East Asia.
In India and other countries of the Indian Subcontinent, vermicelli is known by various local names such as, seviyan in Hindi, Urdu and Punjabi, vaLavaT/ shevaya in Marathi shemai in Bengali, sev in Gujarati, shavige in Kannada, sevalu or semiya in Telugu, and semiya in Tamil and Malayalam. The noodles are used in a number of dishes including a variation of kheer, a sweet dessert similar to rice pudding. Vermicelli are also used in many parts of India to make a popular dish called upma. To prepare it, dry oil-roasted vermicelli are boiled with a choice of vegetables.
Central Asian Kesme and Persian reshteh also resembles vermicelli. Fālūde or faloodeh is a Persian frozen dessert made with thin vermicelli noodles frozen with corn starch, rose water, lime juice, and often ground pistachios.
In East Asia, the term rice vermicelli is often used to describe the thin rice noodles (米粉) popular in China, also known as bee hoon in Hokkien Chinese, mai fun in Cantonese Chinese, วุ้นเส้น (Wûns̄ên) in Thai, ၾကာဆံ (kya zan) in Burmese, and bún in Vietnamese. The term vermicelli may also refer to vermicelli made from mung bean, which is translucent when cooked, whereas rice vermicelli turns whitish when cooked. Mung bean vermicelli is commonly used in Chinese cuisine. In contrast, misua (Chinese: 面线; pinyin: mian xian; Pe̍h-ōe-jī: mī-sòaⁿ) is vermicelli that is made of wheat instead of rice. While superficially similar to bee hoon it has a very different texture and different culinary uses as well.
The fideo is a type of noodle, produced in Europe ever since the Roman times and best known as fideus or fidelis, then spread to Mexican and Latin American cuisine, often referred to by speakers of English as "vermicelli." It is commonly used in chicken soup and in sopa seca, a type of side-dish.
In the United States, vermicelli may refer to the pasta found in Rice-A-Roni, a packaged pilaf-style rice-and-pasta side dish.
Vermicelli, called she'reya (شعريه) in Arabic, is used in one of the most common ways of cooking rice in Egypt. The vermicelli is browned by frying with oil or butter, then rice and water are added.
In Somalia, it is used in a sweet dish called cadriyad, originating from the Yemeni ^aTriyah (عطرية). The vermicelli is browned by frying with butter, then water, sugar and cardamom are added until it has softened slightly. The dish is similar to the Indian kheer. However, no milk or cream is added. It is usually eaten as a dessert or as a side-dish with Somali spiced rice dishes.
Cadriyad is also a common dessert in certain parts of Ethiopia, particularly in the Arab-influenced Harar-ghe region, where it is known as attriya and is served cold, often with a thin layer of custard on top.