IHS

It’s likely that no name in Western history has been spoken more often and in so many forms as the name of Jesus. In medieval Europe, where Latin was the norm in church usage, the most common abbreviation for Jesus was IHS (sometimes rendered IHC), which stood for the first three letters in Latin of the Greek name of Jesus, iota-eta-sigma. The letters took on additional meanings over time, such as Iesus Hominum Salvator (Jesus, Savior of mankind) and has even been adapted to English to mean “In His Service.” To help cultivate a relationship of deep respect and trust with the living God behind the name, write IHS on a small slip of paper and carry it with you.

from: http://www.preparetheword.com/