The Catechism of the Catholic Church teaches us that, "[T]he existence of the spiritual, non-corporeal beings that Sacred Scripture usually calls "angels" is a truth of faith. The witness of Scripture is as clear as the unanimity of Tradition."
Angels are pure, created spirits. The name angel means servant or messenger of God. Angels are celestial or heavenly beings, on a higher order than human beings. Angels have no bodies and do not depend on matter for their existence or activity. They are distinct from saints, which men can become. Angels have intellect and will, and are immortal. They are a vast multitude, but each is an individual person. Archangels are one of the nine choirs of angels listed in the Bible. In ascending order, the choirs or classes are 1) Angels, 2) Archangels, 3) Principalities, 4) Powers, 5) Virtues, 6) Dominations, 7) Thrones, 8) Cherubim, and 9) Seraphim.
Source:Catholic culture.org
