🔼The word Seraphim in the Bible
The Hebrew word seraphim is not really a name but rather what might be considered a genus, not unlike the word Elohim, the genus God. But whether it actually denotes a specific kind of creature can't be determined with the sparse data we have on the word seraphim.
What we do know is that the word שרפים (seraphim) is a plural word; single would be שרף (sarap), or Seraph.
🔼Etymology of the word Seraphim
The word seraph comes from the root-verb שרף (sarap), meaning to burn:
It appears that the Seraphim, who are known in our culture as handsome human-like angelic creatures, were known to the Hebrews as snake-like fireballs. The interpretation of all this requires some preliminary considerations:
In modern times, we like to designate creatures either according to what they look like, or else by some nomenclature that only covers their specific species. A horse is a horse and we don't care what the word "horse" might actually mean. A horsetail is a plant that looks like the tail of a horse, and a sea horse is a fish with a horse-like head. In Hebrew, however, creatures are known mostly according to their behavior, and since creatures usually display multiple defining behaviors, many creatures are known by more than one name — one of the words for lion comes from the verb to gather (see the name Ari) — and it also means that one designations often covers more than one creature. For instance, the word סוס (sus), meaning to flash or dart, denotes both a horse and a swallow (see our article To Be Is To Do).
In the Bible, the word שרף (sarap) is used in two different scenes. Most famous, it denotes the flying, supernatural six-winged creatures that surround God's throne in the vision of Isaiah (Isaiah 6). Much later, John the Revelator also sees a vision of God's throne and sees what seems the same creatures (Revelation 4:8). Both Isaiah and John hear these creatures cry "Holy, holy, holy".
These creatures became known as the Seraphim, and although artists have tried to depict them, we really don't have a clue what they may look like. To start with, we don't know how large they are. They may be very small; small enough even to appear on someone's head (Acts 2:3).
Since their name is derived from a verb meaning to burn, they may look like flames. But if their name was designed to indicate that they did, they would have been known by a word that means flame or fire. They don't; they are known as Burners or Destroyers.
They have six wings (Isaiah 6:2), but God has wings too (Psalm 17:8, 36:7, 57:1, 61:4, 91:4). Since we are made in God's image and likeness (Genesis 1:26), we have "wings" as well, which are obviously not like birds' wings. So the Seraphim's wings may too be not at all like birds' wings.
Seraphim have faces but their wings cover them, and they may look like anything. They have feet, also covered by their wings, but not necessarily human feet, and the word for feet is so general that we still don't know anything about their appearance.
And the question of whether or not Seraphim are angels can neither be answered. Biblical angels usually either look like humans or sound like them, and we don't know if there are separate species of angels, or even if they exist as autonomous individuals. Angels, Seraphim, Cherubim and spirits may be ripples on an ocean, for all we know. What we do know is that the Bible clearly indicates that there is more to creation than just us. And although to us The Others may be seem to be more like God than like us, to God we and they are much more similar than any of us is to Him.
The other famous scene in which the word seraphim is prominently featured deals with the attack of the "fiery serpents" on Israel in the wilderness (Numbers 21:6), which literally reads, "And YHWH sent among the people the seraphim serpents". The word for serpent, nahash, is related to the words for bronze and the verb to divine, and the serpent scene of Numbers 21 may be about more than just an animal attack.
In his letter to the Ephesians, Paul writes about spiritual armor, and mentions the evil one's fiery darts, to be warded off with the shield of faith (6:16). The Greek word for evil one is poneros, which comes from ponos, meaning labor, sorrow or pain. The word for dart is belos, which comes from the verb ballo, meaning to cast (hence our word ballistic), and which indicates an entity (arrow or spear) that flies through the air. And the word for fiery comes from pur, from which we get our word fire.
Whatever the allegorical charge of the event might be, the snake attack on Israel is certainly not a single, quick assault. The snakes remain among Israel for a substantial period of time, until the people come to Moses and ask him to remove the snakes from among them.
The Lord then instructs Moses to create a שרף (sarap) and set it on a standard. Moses interprets the making of a seraph by making a "bronze serpent" — a nahash nahashet; twice the word nahash — and anyone who looks upon it is saved from the real ones. Apparently, the image of the bronze serpent was so impressive that the Israelites gave it a name — Nehushtan — and burned incense to it until king Hezekiah destroyed it (2 Kings 18:4). Later still, Jesus compares His imminent crucifixion to Moses' raising of the bronze serpent (John 3:14, also see 8:28 and 12:32).
The serpentine seraphim return in Isaiah 14:29, where the prophet foretells the destruction of Philistia, "from the root of the snake (nahash) comes a viper (tzepa, a word that indicates a snake producing venom), and his fruit (is) a flying seraph". Actually, the word "flying" may also mean "dark"; see the name Ephah. The flying or dark seraph returns in Isaiah 30:6, where it is listed among the beasts of the Negev.
The word Seraphim means Burners or Destroyers.