In the Royal Arch degrees, there is a ceremony called the "passing of the veils". The veil, still used in many cultures and ceremonies around the world, has several symbolic significances.
In an old Royal Arch lecture, possibly as early as 1800, reads "the Veil of the temple signifies the Son of God, Jesus Christ, hanging upon the Altar of the Cross, as the teue veil between God and us... In this context, the word veil alludes to a promise, or bond. In ancient Rome a red veil, or a veil with red stripes, distinguished newly-married women from the unmarried, again signifying a bond between them and their husbands. It is also worn by widows, who made a profession of continence. The veil is also a symbol of the pre-enlightened state, hidden knowledge, secrecy, illusion, and ignorance. It conceals, but is often intended as protection rather than deception; it might also be a mark of modesty and virtue in many cultures, often worn by women and girls to display their lack of vanity. In earlier times, women wore veils to Church, to indicate their removal from the vanities of this world. Nuns too were veiled, as the expressions "to take the veil" for entry into cloister life.
According to the famed historian Josephus, there were four veils that adorned the Tabernacle. The white veil signified the earth, the blue veil signified the air, the purple veil signified the sea (because the purple color comes from murex, a shell-fish) and red signified fire. Today, the Passing of the Veils ceremony uses three veils, sometimes four. Veils are also often used to cover a religious, or holy, object to keep it from the public. The significance again is less to conceal something; rather is signifies something special. In Exodus 34, we learn that when Moses came down Mt. Sinai, "the skin of his face shone", which he had to cover with a veil as the people were unable to look upon his shining face. The Koran (7:44) mentions that a veil divides the damned from the chosen. The unbelievers tell the Prophet in Koran (41:4) that "between us and thee there is a veil".
The verb, to reveal, comes from re-veil, which signifies to pull back or to cover again something with a veil.
Saint Ludmilla (860-921) was said to have been strangled by a veil, and hence the symbol is associated with her, and is the patron Saint of widows.