The word veil
is used exclusively to refer to the hanging curtain in front of the most holy place in the tabernacle. As the result of sin, uncleanness would penetrate into the area where priestly duties would often take place. Purification of the holy place was necessary.
6 and the priest shall dip his finger in the blood and sprinkle part of the blood seven times before the LORD in front of the veil of the sanctuary.