I'm going to begin this post by repeating (with small adjustments) some of what I said in this now possibly defunct theory. Much of that post I already possibly retracted here.
The KJV of the Book of Revelation uses the word "Lamb" 29 times, all but once of Jesus. All of them are the same Greek word (Strongs number 721), but in 3 different forms. Arnion/Arniou/ArniO.
This word however appears only once in the NT outside Revelation, in John 21:15. There however it is a form distinct from any of the 3 used in Revelation, Arnia. I'm not sure but I think that could qualify as a feminine form, while the 3 in Revelation clearly do not. There it is used of Believers not of Jesus. But unlike in English translations the Greek text doesn't seem plural there, like Jesus is calling The Church as a whole His Arnia.
The suggestion has been made before that "Lamb" is not an accurate translation of this word, and even been suggested before that it should be "Ram". It's controversial because this word is rare even in Ancient Greek usage outside The Bible. Other Greek words are known to have existed for Lambs and Rams and Goats, the other words for Ram aren't used in the New Testament however (I give no credence to the Septuagint). The main one would be Krios, the Greek name for the constellation Aries, The Ram.
When John, this same Author, in his Gospel quotes in Greek John The Baptist calling Jesus "The Lamb of God" in 1:29&36 he uses Amnos (Strongs number 286). Likewise Acts 8:32 and 1 Peter 1:19 when alluding to Isaiah 53:7 and the Passover Lamb also use Amnos, though Peter spelled it Amnou. In Hebrew also Isaiah 53:7's "Lamb to the Slaughter" uses the same word used of the Passover Lamb in Exodus 12, Strongs number 7716, Seh.
Revelation 5 tells us the Arnion has seven horns. Revelation 13:11 tells us the Beast out of The Earth has 2 horns like an ArniO. While lambs do have horns they're very small and not too noticeable, and so outside Revelation no Biblical references to Lambs mention that they have horns. But they are mentioned in reference to other animals, including the Ayil, and Goats.
And the Shofar (one of two Hebrew words translated Trumpet) was specifically a Trumpet made from a Ram's horn. It's the Shofar sounded on the Yom Kippur proceeding the Jubilee Year in Leviticus 25:9. And traditionally Rams horns are sounded on Yom Teruah, though the Biblicalness of that is debated by Kariates and others.
In the Book of Joshua chapter 6 at the fall of Jericho seven Shofars were sounded. If Arnion means Ram then it would be natural to speculate a connection between the seven horns of the Arnion in Revelation 5, and the seven trumpets sounded by the seven angels later. Other have argued those seven angels are also the seven spirits refereed to, though I've disagreed with that in the past, but I've now updated that post. And Jesus is described as having a voice like a Trumpet.
The repeat is over now.
While I had argued very recently before for the idea of it meaning Ram, my considering that Ayil maybe doesn't mean Ram weakens much of that.
I also learned recently that Shofars are not always Ram's Horns, they can be among other things, Goat's Horns too. (The KJV using Ram's Horn in Joshua 6 is mistranslated, the word used there is actually Jubilee). So the Shofar part of the Ram theory about the Seven Horns in Revelation 5 can also apply to Goats.
Arnion meaning Goat has not been argued for before from what I can find. But as I said Arnion was very rarely used.
The End Times are viewed as being largely about the Fall Feasts rather then the Spring Feasts. While Numbers 28-29 called for a lot of sacrifices on nearly all the Leviticus 23 Holy Days. Only one Fall Holy Day day is affiliated with a specific special Sacrifice the way Passover is. And that's Yom Kippur, The Sin Offering which was a Goat, described in detail in Leviticus 16.
A Greek word for Goat is used 3 times in the New Testament, in 3 different forms (Strong number 2055 and 2056). EriphOn and Eriphia in Matthew 25:32-33 the Sheep and Goats judgment, and Eriphon in Luke 15:29. In Luke it's at the end of the Prodigal Son parable, used by the older brother to disparagingly describe the animal that had been offered for him in comparison to his brother now.
So none of those are of a Goat as representing Jesus, and possibly all meant to be derogatory. And neither is by the same human author as Revelation.
While they begin with different letters Ar and Er could reflect a common etymological origin.
And the thing is Hebrew has two different words for Goat or Kid (the KJV translates both as both at different times).
Sayir (Strong number 8163) and Ez (Strong number 5795). The two words are often used in the same verse. Anytime you see "a kid of the goats", Kid is Sayir and Goat is Ez.
Ez first appears in Genesis 15:9, the first appearance of several words for the Sacrificial Animals. Saiyr first appears in Genesis 37:31 which also uses Ez. Both are used in Leviticus 16, but Saiyr much more frequently. And both are used of the Sin offerings called for in Numbers 28-29. And both are used of the He-Goat or Rough-Goat that represents Greece in Daniel 8.
Azazel, the name of the Yom Kippur Scapegoat, is a compound word combining Ez and Azal (Strongs 235) In a sense both Yom Kippur Goats represent Jesus, He both carries our Sins and Dies for them. But I've also argued for a sense in which the Azazel goat could represent Satan, the Antichrist/Falseprophet or the unbelievers in general. This could make sense with Goats representing those cast into Aionios fire (sheeps and Goats judgment). So maybe that has something to do with the second beast having horns "like an ArniO".
In both Leviticus 17:7 and 2 Chronicles 11:15, Saiyr appears and is translated "devils" in the KJV. The context is describing idols or false gods that are being worshiped. Perhaps similar to the Greek goat-god Pan, or the Egyptian Goat of Mendes. In Isaiah 13:21 and 34:14, Saiyr is translated Satyr. A Greek mythological term that originally just refereed to the male counterparts of the Meaneds of Dionysus, but in time came to be thought of as Faun like creatures, which I think is what the KJV translators had in mind.
Isaiah 34 is about Edom, which is interesting since Saiyr is spelled the same as Seir in Hebrew, which is taken to mean Hairy and used to describe Esau's hairiness in Genesis 27. Also in Genesis 27 Jacob uses Goat skins to mimic the feel of Esau's hairiness. Song of Solomon 4:1 and 6:5 use Ez to describe the thickness of Shulamith's hair.
Ez seems to have no feminine equivalent used in Scripture. But Saiyr has Saiyrah, used in Leviticus 4:28 and 5:6. (Correction, Uzzah is a feminine form of Ez, but it only ever appears as a name.)
I'm thinking maybe Eriphon should be viewed as the Greek equivalent to one of those Hebrew words and Arnion the other. Which is which I could go either way on, but I'm leaning towards Eriphon as Saiyr since Paul uses Esau as an idiom for the Gentiles in Romans 9-11. The Septuagint I already know uses Arnion for neither, fortunately I don't trust it. But it may be interesting to see how it uses Eriphon. I don't feel like doing that myself right now, maybe for a future follow up.
Josephus in Antiquities of The Jews Book 3:231 says "ho men gar kata agnoian eis touto propesôn arna kai eriphon thêleian tôn autoetôn prospherei". Which William Whiston translated, " But if a person fall into sin by ignorance, he offers an ewe lamb, or a female kid of the goats, of the same age;". Arna is another form of Arnion, of it's NT appearances most similar to Arnia.
Josephus was not doing a Greek Translation of Scripture. But he was here clearly alluding to one of the verses where the feminine Saiyrah was used. Both verses also use Ez. Leviticus 4:28 includes no animal names besides those, but 5:6 does. It sounds like Josephus intent here was to be talking about Sin offerings, which are defined as being for sins committed in ignorance, which makes 4:28 the better fit. But later the same account mentions Lambs, so it's still unclear even what Josephus meant Arna to mean.
Modern Satanism's use of Goat imagery has caused Christians to develop an unhealthy aversion to Goat imagery. Even Torah observant Christians will talk about goats positively only when it's about Torah verses that require them too. I've talked about the negative references to goats here, but let's not forget based on Leviticus 16, a Goat can represent Jesus just as much as a Lamb can.
Maybe Arnion isn't Greek in origin at all. Because for other subjects I've attempted to research the Etymology of Arnon, the name of a River mentioned in The Hebrew Bible. And found that name has been suspected to be related to Arabic, Aramaic and Syriac words for a type of Goat.