Today is commemoration of the Holy Name of Jesus, a feastday which was reinstituted by Pope John Paul II after being dropped from the Roman calendar during the 1969 revisions (the Feast erstwhile known as the "Feast of the Circumcision.")
The letters "IHS" are ubiquitous in Churches, on altars, on vestments, etc. and they are sometimes mistakenly represented with periods between the letters (I.H.S.) as an acronym for "Jesus Hominum Salvator." Originally, however, they were intended to represent the first three (capital) letters of the Most Holy Name of Jesus in Greek (Iota, Eta, Sigma).
"How are we to pronounce the sacred name of Jesus? . . . It is not enough to say it with your lips; it must be engraved upon your heart."
St. Francis de Sales