Like a sacrament, the Church is the visible sign of Jesus Christ, who is the perfect sign of the Father's saving love. As such, she has four distinguishing characteristics or marks.
The Church is a symbol of God and his son, Jesus Christ where people go to pray to both of them. Everybody knows that God is forgiving, as his love will save us from our sins. The word mark means the same as characteristic, so that is correct too.
