The Church often uses common symbols to illustrate things; the problem comes when these common symbols lose their meaning! One example is the monogram "IHS" on sanctuary objects:
In the Greek New Testament the name of Jesus is spelled IhsouV (pronounced as yā-sous). In all capital letters it would be IHSOUS. Take the first three letters, IHS (Iota, Eta, Sigma) and you have IHS in our script.