Thái

Thái is a versatile term in Vietnamese that can refer to several unrelated concepts, including a surname, an ethnolinguistic designation, a Sino-Vietnamese morpheme, and the Vietnamese name for Thailand and Thai people.

As a surname, Thái is a Vietnamese family name and is found among Vietnamese people today. It can have origins linked to Chinese surnames such as 太 or 泰, and it may appear in given names or in combination with other words in Vietnamese personal naming.

As an ethnolinguistic designation, Thái commonly appears in the phrases người Thái (the Thai people) and tiếng Thái (the Thai language). In Vietnam, there are communities connected to Tai-speaking groups, some of which cross national borders into neighboring countries. The term also appears in the name for the country of Thailand in Vietnamese: Thái Lan.

In Sino-Vietnamese vocabulary, thai or thái is a morpheme meaning greatness or grandness and is used in many compounds. Examples include thái bình (peace and stability), thái quá (excessive), and thái độ (attitude). This usage reflects historical Chinese influence on Vietnamese vocabulary and is found in formal or literary contexts.

In summary, thuần Việt uses of Thái include a surname, references to Thai ethnicity and language, a common Sino-Vietnamese morpheme for building words, and the Vietnamese name for Thailand and its people.