Well in my head anthro refers to bipedal human like (anthropomorphic)

And feral relates to natural wild animals- quadrupeds that walk on 4 legs.

Thats just how i look at it as my own definition and difference.

I think its just a "Fandom Term" Basically "Furry Speak". Like the word Yiff.
In the Dictionary it means this....but in the Furry Fandom, it means that.

I think like someone else said, it's referring to the more "wild" body type - as in, this is an animal as it would be in the "wild". It's a way to easily differentiate between an anthro (human, "evolved" body type) and a feral (animal, "wild" body type).

It's...a lot easier to type and say than "quadrupedal".

Words change their meanings over time when people use them in communities.

But what about domestic animal OC's? It doesn't make sense for them.

Still applies to them. Feral just means the character has a normal animal body instead of a human like Anthro body. It has nothing to do with the wilderness at all.

I think the implication is (sort of) that an anthro is "evolved", therefore, less wild, and a "feral" would be unevolved, closer to its "wild" ancestors.

It's just an easier word to use than "quadruped", and like I said, words change their meaning when used in community settings. "Anthro" refers to an animal who walks and talks like an evolved human, and "feral" refers to an animal that looks like animals in their original, "wild" form. Even if some characters may not fit this exactly (a "feral" character who walks on two legs, or a "domesticated" animal like a hound dog who walks on four legs but lives in a house), the fandom probably naturally needed easier terms for these than "bipedal" and "quadrupedal". "Anthro" and "Feral" are just easier to say, and now everyone knows what they mean by their definition within this fandom.

There are words like this that bother me, too, because the definition has changed over the years to mean something inaccurate but...that's just how it goes. We need ways to easily express what kind of commissions we're open for, etc. (For example, I'm way more comfortable with ferals than anthros because I don't understand how humans stand up, haha).

Its cause they are a wild animal, not the humanoid type animal character.

Because calling them quads doesn't apply to birds, snakes, fish, or anything that doesn't have four legs.

Feral is just more or less quicker/easier to describe characters that are shaped in their more natural or "wild" state in comparison to being anthro which is unnatural all together.

The same is also true of anthro. Just having human intelligence/emotions is enough to classify as anthro. Most of the time its used to describe a human like body.

feral also means resembling a wild animal. Which when compared to an anthro the quadrupeds do greatly resemble a wild animal regardless of domestic or not imo

All of the young Millennials and Gen Z'er's in the fandom won't remember this, but the term "feral" for these types of characters is actually somewhat recent. Back in the olden times of 10+ years ago give or take, the common term for characters like the ones that appeared in animated movies like Balto, The Lion King (1994), The Aristocats, The Fox and the Hound, etc., were "talking animals". Bipedal anthro characters in contrast were called "anthros," "furries," or the really archaic term "funny animals." I only call these quadruped characters "ferals" nowadays because that is what the younger folk in the fandom predominantly call them. If I see someone calling quadruped animal characters "talking animals" it's a good hint that they've been in the fandom for 20+ years already like I have.

I've given up on correcting terminology :/ A human can be "feral."

I used the term "physically non-anthropomorphic" but furs wouldn't understand that term at all :/

I've never particularly liked the term but it's pretty commonly used. My unicorn uses an anthro/bipedal form but he's always been a quadruped. I suppose for me it's because I see a difference between an intelligent, talking creature and a regular wild one and the use of 'feral' can lump both of those together.