All jokes aside, I did try to see if there was a relation. I didn't do it for both parts of the word, too much work, but it's unlikely teriyaki is related to greek in any meaningful way. the suffix Yaki can ultimately be traced to Proto-Austronese, like many southeast asian languages. This is a seperate language family from Proto-Indo-European, the ancestor language of Greek and many other languages. these groups may share a common language ancestor, but may also not. Language developed hundreds of thousands of years before the earliest reconstructed proto languages, so we simply don't know if they developed in parallel in totally disparate cultures, or if they both developed from a shared language that has been lost to time.