Ish was the home of the Ishtar, but no the Ishi Tib. The Ishi Tib were from Tibrin. Lots of people made that mistake. This was further complicated by the fact that there were a few Ishi Tib who lived on Ish, and seemed to enjoy confusing people. This was one reason why Ish was sometimes used to describe an approximation. It also became a stand-in a nasty bodily function, which the people of Ish were not real happy about.