What is the Thai word for "which"?

The Thai word for "which" is หนึ่ง (neung), meaning "one." Instead, the correct correspondence for "which" in Thai is ไหน (nai). This word is used to indicate a choice or selection among a group, similar to the use of "which" in English when asking about options.

For example, in a sentence, if someone wanted to ask "Which book do you want?" in Thai, they would use ไหน to convey the selection aspect, asking the listener to specify from among the available options.

The other choices serve different purposes: ทุก (thuk) means "every" or "all," indicating totality rather than choice, and บาง (bang) means "some," which also doesn't fit the context of selection. Thus, the use of ไหน is appropriate for inquiries about specific items or options, aligning with the function of "which" in English.