What do maror symbolize?

Maror is a relish made of chopped fruit, nuts and wine. It is one of the essential foods of a Passover seder. If it represents anything, it represents the mortar used by the Israelites in their slave labor for Pharoah. In practice, it serves to cut the intensity of the bitter herbs that are another essential food at the seder. Straight horseradish is not very palatable. Horseradish plus maror burns, but you can eat it.