Wat, chedi, prang, ubosot and wihan: Thai temple words

The short answer

A wat is the whole temple, not one building. The Royal Society of Thailand's dictionary defines it as a religious place that usually has a bot, a wihan and dwellings for monks or other clergy.[1] Inside it, the words a visitor most needs separate two kinds of tower (chedi and prang) and two kinds of hall (the ubosot, or bot, and the wihan). The definitions below are the Royal Society's, in XTOUR's translation; the examples are from the Fine Arts Department's pages for Ayutthaya and Sukhothai and from Wat Pho's own site.

Official English is a poor guide. The same Thai building is a "stupa", "pagoda", "chapel", "assembly hall" or even a "church" depending on whose page you read, so this page keeps the Thai word as the key and gives the English labels each source uses.

Chedi and prang: two kinds of tower

The Royal Society defines a chedi as a structure built in a shape like a straw stack, with a pointed top, that enshrines revered objects such as relics; the word comes from Pali cetiya and Sanskrit caitya. A prang is a structure with a tall top shaped like a corn cob, crowned with a phaka-pod finial, and the dictionary adds that a chedi with such a top is called a chedi yot prang.[1] XTOUR's reading: a prang is a shape, and it can be a form of chedi, so the two words are not opposites.

Ayutthaya shows both. The Fine Arts Department describes Wat Phra Si Sanphet as having three "bell-shaped stupas" as its principal buildings, each enshrining royal ashes, with a mondop on the west side of each.[2] At Wat Chaiwatthanaram, which it places by the Chao Phraya River "outside the western island of Ayutthaya", it describes a large principal prang and corner prangs on one base, ringed by a cloister with eight prang-topped structures, nine tops in all.[3] At Ayutthaya's Wat Mahathat, the principal prang held the relics, with four directional prangs around it.[4]

An official disagreement sits here. ICOMOS's 1991 evaluation for UNESCO calls the prang Ayutthaya's main architectural feature, "a reliquary tower which did not exist at Sukhothai".[8] The Fine Arts Department's page for Wat Si Sawai at Sukhothai describes three Lopburi-style prang influenced by Khmer style, at a site it says was probably a Brahmin shrine before it became a Buddhist temple.[5] ICOMOS's own evaluation of Sukhothai, from the same year, lists among the old town's principal monuments "an impressive prang (reliquary tower typical of Ayutthaya art) from a somewhat later period".[9] XTOUR reports all three and does not decide which buildings ICOMOS had in mind. At Sukhothai's Wat Mahathat, the department describes the main stupa as built in the "Bua Tum" style, "a unique architecture of Sukhothai".[6]

In Bangkok, Wat Pho's site uses yet another vocabulary. It calls its four 42-metre Phra Maha Chedi "huge pagodas", and its four corner towers "Phra Maha Stupa, or Phra Prang", a type it terms "Phra Agghiya chedi".[15][14] TAT's 2017 press release on Wat Arun's restoration calls the temple's 66.8-metre main feature a "pagoda" throughout.[19] XTOUR could not open Wat Arun's own website on 9 October 2026 and has read no official page naming that tower's form, so it does not label it here.

Ubosot (bot) and wihan: two kinds of hall

The ubosot, short form bot, is in the dictionary's words the place where monks meet to perform formal acts of the Sangha, such as reciting the Patimokkha and ordination, with sima (sema) marking its boundary. The wihan is defined as a place where a Buddha image is enshrined, paired with the bot; the same word can also mean a wat or a monks' dwelling.[1]

The dictionary ties the boundary stones to the bot alone: it defines sema as the marker of the bot's boundary.[1] Wat Pho's page on its Kampaengkaew describes a marble wall around its main hall with eight sheltered gates and eight sculpted boundary stones, Bai Sema.[13] XTOUR's reading: sema stones set around a hall identify it as the ubosot.

English labels blur the two. Wat Pho calls its Phra Ubosot "the Assembly Hall for performing the monastic ritual", and calls the Phra Vihara of the Reclining Buddha "the assembly hall" too.[12][11] The Fine Arts Department's English pages call the ubosot "Phra Ubosot" at Wat Chaiwatthanaram, where it stands east of the cloister, and "the chapel" at Ayutthaya's Wat Mahathat.[4][3] Its Sukhothai page for Wat Mahathat lists "temples, churches, Mon Dops" among the buildings.[6] XTOUR's reading is that "churches" renders bot, since the dictionary says the word bot is extended to other religions' places of rites, including a Christian bot.[1]

The rest of the compound

A wat is often walled into two parts. The dictionary's phutthawat is the part with the bot, wihan and chedi used for the Sangha's acts, walled off from the sangkhawat where monks and novices live; it gives Wat Phra Kaew as a wat built for those acts alone, with no sangkhawat.[1] Wat Pho's history page describes the same split in its own spelling, a sacred Buddhavas and a residential Sangghavas.[10] See the Grand Palace and Wat Phra Kaew for that temple.

Other words a visitor meets, as the dictionary defines them:

• Rabiang (ระเบียง): a row building surrounding an ubosot or wihan, the cloister.[1] Wat Pho describes double cloisters around its main hall, linking four directional wihan.[16]
• Wihan khot (วิหารคด): an elbow-shaped wihan housing Buddha images, mostly at the four corners of the phutthawat.[1] Wat Pho has four, at the corners of the wall around its main hall.[17]
• Sala rai (ศาลาราย): pavilions built one by one in a line around a bot or wihan.[1]
• Mondop (มณฑป): a large square building with a tiered pyramidal roof.[1] The word names a form, not a use: Wat Pho's Phra Mondob is its scripture hall, while at Sukhothai's Wat Si Chum the mondop is the main building and houses a Buddha image.[7][18]
• Ho trai (หอไตร): a hall for keeping the Tripitaka, the Buddhist scriptures.[1]
• Phra that (พระธาตุ): relics of the Buddha and of arahants; a that chedi (ธาตุเจดีย์) is a chedi that enshrines them.[1] This is the "mahathat" in temple names such as Wat Mahathat, in XTOUR's reading of the word.
• Sathup (สถูป): an upturned-bowl structure enshrining relics, the word English renders as stupa; the dictionary notes it is sometimes paired with chedi.[1]

One image, two official accounts

The words also help read where things moved. The Fine Arts Department says the Royal Viharn at Wat Phra Si Sanphet housed Phra Si Sanphet, a standing Buddha image 8 metres high, and that Rama I had its surviving bronze core enshrined in the Si Sanphet Dayan chedi at Wat Pho.[2] Wat Pho's page for that chedi says it was built to cover the ruined image, which it gives as 16 metres high and brought from the royal palace in Ayutthaya.[14] The two pages agree on the chedi and disagree on the height; XTOUR does not settle it.

Living temples and ruins

The words on this page apply to ruins and living temples alike. The Fine Arts Department describes Ayutthaya's Wat Mahathat as deserted after the city fell in B.E. 2310, with only the base of its main prang left by the reign of Rama V.[4] Wat Pho, by contrast, describes itself as a first-grade royal monastery whose residential quarter is the monks' living section.[10] For the parks themselves, see Ayutthaya Historical Park from Bangkok, Sukhothai or Ayutthaya and what UNESCO inscribed at Ayutthaya and Sukhothai; XTOUR treats the town of Sukhothai as a base for its historical park, not as the park itself.

What to wear and how to behave in a living wat is a separate question, answered from the temples' own rules in visiting Thai temples: the official rules. The Wat Pho massage school explainer covers the sala rai where the temple says its school teaches.

What XTOUR does not know

• How the Royal Society's definitions map onto every building: the dictionary defines words, not particular temples, and XTOUR applies a word to a building only where an official page names it.
• What form Wat Arun's main tower takes in an official description, since XTOUR could not open the temple's site.
• The height of the Phra Si Sanphet image, on which the Fine Arts Department and Wat Pho disagree.
• XTOUR has not verified opening hours, tickets or access for any temple or ruin named here. For the cities, see Bangkok and Ayutthaya.