Strictly speaking a wat is a Buddhist sacred precinct with a vihara (quarters for bhikkhus), a temple, an edifice housing a large image of Buddha and a structure for lessons. A site without a minimum of three resident bhikkhus cannot correctly be described as a wat although the term is frequently used more loosely, even for ruins of ancient temples. As a transitive or intransitive verb, wat means to measure, to take measurements; compare templum, from which temple derives, having the same root as template.
In everyday language in Thailand, a wat is any place of worship except a mosque (Thai สุเหร่า surao or มัสยิด masjid; a mosque may also be described as โบสถ์ของอิสลาม - bot khong itsalam, literally "Islam church") or a synagogue (Thai สุเหร่ายิว - surao yiw). Thus a wat chin is a Chinese temple (either Buddhist or Taoist), wat khaek is a Hindu temple and wat khrit or wat farang is a Christian church, though Thai โบสถ์ (โบสถ์ bot) may be used descriptively as with mosques.
In Cambodia, a wat is used to refer to all kinds of places of worship. Technically, wat generally refers to a Buddhist place of worship, but the technical term is វត្តពុទ្ធសាសនា wat putthasasana. A Christian church can be referred as វិហារយេស៊ូ vihear Yesaou or "Jesus vihear". Angkor Wat អង្គរវត្ត means "city of temples".
According to Thai law, Thai Buddhist temples are of two types:
- Wat (วัด; wat) are temples which have been endorsed by the state and have been granted wisungkhamasima (วิสุงคามสีมา), or the land for establishing central hall, by the king. These temples are divided into:
- Samnak song (สำนักสงฆ์; samnak song) are temples without state endorsement and wisungkhamasima.
A typical Buddhist wat consists of the following buildings:
- chaidei or chedi (Khmer ចេតិយ), (Thai เจดีย์) (from Sanskrit: chaitya, temple) - usually conical or bell-shaped buildings, often containing relics of Buddha
- vihear (Khmer វិហារ),wihan (Thai วิหาร) from Sanskrit: vihara) - a meeting and prayer room
- mondop (Thai มณฑป) (from Sanskrit: Mandapa) - a usually open, square building with four arches and a pyramidal roof, used to worship religious texts or objects
- sala (Khmer សាលា), (Thai ศาลา) (from Sanskrit: Shala - School, from an earlier meaning of shelter) - a pavilion for relaxation or miscellaneous activities
- bot โบสถ์ or ubosot อุโบสถ์ (from Pali uposatha) - the holiest prayer room, also called the "ordination hall" as it is where new monks take their vows. Architecturally it is similar to the vihara; the main differences are the eight cornerstones placed around the bot to ward off evil. The bot is usually more decorated than the viharn.
- hall (Thai หอไตร) - library where Buddhist texts are kept
- drum tower (Thai หอกลอง)
- bell tower (Thai หอระฆัง)
- multipurpose hall (Thai: ศาลาการเปรียญ, study hall) is a building in a wat. 
The living quarters of the monks, including the กุฏิ (pronounced kut, kutti or kuti - monk cells) are separated from the sacred buildings.
The roofs of Thai temples are often adorned with chofas.
|Look up wat in Wiktionary, the free dictionary.|
Some well-known wats include:
- Angkor Wat, Siem Reap
- Wat Preah Keo, Phnom Penh
- Wat Botum Vathey, Phnom Penh
- Wat Moha Montrey, Phnom Penh
- Wat Ounalaom, Phnom Penh
- Wat Phnom, Phnom Penh
- Wat Bakan, Pursat
- Lan Na (Northern Thailand)
- Delahunty, Andrew (23 October 2008). From Bonbon to Cha-cha: Oxford Dictionary of Foreign Words and Phrases. OUP Oxford. p. 373. ISBN 978-0-19-954369-4.
- ราชกิจจานุเบกษา, ประกาศกระทรวงธรรมการ แผนกกรมสังฆการี เรื่อง จัดระเบียบพระอารามหลวง, เล่ม ๓๒, ตอน ๐ ก, ๓ ตุลาคม พ.ศ.๒๔๕๘, หน้า ๒๘๔
- Pura, Balinese temples
- Candi, temples of ancient Indonesia, especially Java
- Kyaung, Burmese monastery