What is tho?

I'm sorry, but the term "tho" is quite broad and can refer to a couple of different things. In casual slang, "tho" is often used as a short form of the word "though," frequently seen in informal writing and social media to add emphasis or contrast. For example, "I didn't like the movie, tho."

If "tho" refers to something else specific, such as a name, acronym, or a concept, could you please provide more context or clarify what exactly you are asking about? That way, I can help you better.