A psalm is a sacred song or text used in worship. It especially refers to The Book of Psalms, which is part of the Hebrew Bible and the Christian Old Testament.
The word psalm derives from the Ancient Greek word psalmos, which means "song sung to harp music", referring to the fact that these songs or poems were often accompanied by harp music.
The correct pronunciation of psalm is Saahm.
Both the "P" and the "S" in psalm are both silent. The "a" psalm is elongated and pronounced with a short "a", which means it is pronounced with an "ah" sound. However, the "ah" is pronounced in a much more open manner, like the word "palm".