The word Seraphim is the plural of the word Seraph. So when anyone speaks of Seraphim they are speaking of more than one Seraph angel. In Hebrew, the word means “burning one” associating the Seraphim with flames or fire.
Seraphim Angles are mentioned by name only once in the Bible. They appear in a vision of the Prophet Isaiah described in the Book of Isaiah in the Old Testament. Isaiah Chapter 6 verses 1 through 3 read: “In the year that King Uzziah died, I saw the Lord seated on a throne, and the train of his robe filled the temple. Above him were Seraphim, each with six wings, with two wings they covered their faces, with two they covered their feet, and with two they were flying. And they were calling to one another, holy, holy, holy is the Lord Almighty, the whole earth is full of his glory”.
Although they are not called Seraphim, the Book of Revelation Chapter Four verses 7 and 8 describe creatures that could only be Seraphim: “The first living creature was like a lion, the second was like an ox, the third had a face like a man, and the fourth was like a flying eagle. Each of the four living creatures had six wings and was covered with eyes all around, even under his wings. Day and night they never stop saying: “Holy, holy, holy is the Lord God Almighty, who was, and is, and is to come.”
Some biblical scholars think that the angel set to guard the entrance to the Garden of Eden is a Seraph named Uriel, whose name means “Fire of God” and this angel bears a fiery sword (Geneses chapter 3 verse 24).
The great Jewish philosopher Maimonides in his Mishneh Torah describes ten orders or ranks of angels with Seraphim being fifth. However, according Saint Thomas Aquinas in his The Summa Theologica and in other works such as the Celestial Hierarchy regarding Christian Angelology, Seraphim Angels are at the top of the Angel hierarchy being closest to God Himself.
Although this is the only by name mention in the biblical canon, Seraphim are mentioned several times in the non-Canonical Book of Enoch. The apocryphal Book of Enoch names some Seraphim. Those named include Kemuel, Nathanael and Gabriel.
While almost all angels were created by God directly, at least one Seraph called Metatron was originally a very righteous man named Enoch who was transported to Heaven and made an angel.