Thay

Thay is the non-diacritic ASCII rendering of the Vietnamese word thầy, which is used as a title and noun meaning “teacher” or “master.” In proper Vietnamese orthography, the word is written with diacritics as thầy. The diacritic-free form thay appears mainly in older texts, in digital environments that omit diacritics, or in transliteration systems that do not display tone and vowel marks. There is no separate vocabulary item in Vietnamese that is widely recognized as “thay” apart from this orthographic variant; its meaning and usage are the same as those of thầy when diacritics are added.

In Vietnamese, thầy is a respectful title for male teachers or instructors and can be found in compound terms such as thầy giáo (schoolteacher) or thầy bói (fortune-teller). Beyond education, the term can also function in contexts of mentorship or mastership, including traditional, religious, or craft settings, to denote someone who possesses specialized knowledge or skill and serves as a guide or teacher.

Usage notes:

- Gendered form: for female teachers, the equivalent honorific is cô.

- Diacritics matter: changing to the non-diacritic form thay can alter readability and precision, especially for learners of Vietnamese.

- Etymology: thầy derives from the Vietnamese lexeme for “teacher/master,” with cognates in historical and religious contexts.

See also: Vietnamese language, Thầy (title), Education in Vietnam.