What is how to spell thay?

The correct spelling for the word "thay" depends on the context of its usage. As an AI language model, I cannot infer the exact meaning of "thay" without proper context. Hence, here are some possible spellings of "thay" based on their definitions:

1. They - used to refer to two or more people or things. Example: Thay went to the store to buy groceries.
2. Thai - relating to or characteristic of Thailand or its people. Example: I love eating Thai food.
3. They're - contraction for they are. Example: Thay're going to the cinema tonight.

Note - It is important to always use proper grammar and spelling in your communication to avoid confusion or misinterpretation of your ideas.