Sampi or Disigma is a mysterious Greek symbol. Its meaning is still debated today. At the moment it is thought by some that it is a letter for the number "900" used in the system of Greek numerals. And others believe it to be a replacement of 'san'. Before that, it was a letter that was used in the Greek alphabet in a few Greek cities in the 5th century BC. At that time, it looked like or . It was probably pronounced like "ts" or "tch" in the dialect of those cities. Over time, it was changed from to or and at last to .