Bay and Brown?

This may have already been asked, but I see a lot of posts on whether a horse is bay or brown and I get confused. I was taught that any horse with an agouti factor was bay to some extent from seal bay (At), bay (A), and blood bay (A+) with color restriction going from least restrictive to most restrictive.
So am I wrong on these colors or is it something that varies from breed to breed and place to place? (ie. Rabbits and being either black tort or sooty fawn, same color, called different things in US vs. UK).
If I'm not wrong on the genes and it is something that just depends on where you live or what breed you raise could someone help me on, for example, which situation it is okay to call a horse brown or seal bay? Also how much restriction is the line between brown and bay? Are only A+ agouti factor horses considered bay or does it depend on the strength of the particular A agouti factor on a specific horse to depend on whether it's brown or bay?
Sorry if my wording is too confusing, I'm just a little lost on the subject, lol.

Seal bay = brown = At. You will (hopefully) find more and more people using brown as a term separate to bay now that we have a test and know that "brown" is a correct colour and isn't just a bay with sooty or other such things.

Also - what you have called "blood bay" with the A+ designation, is most often referred to as wild bay.

Ah, okay, thank you. So I guess whether they're called seal bay or brown would be completely dependent on a registry's preference?
Also, I've also heard it called wild bay as well as blood bay. I just learned blood bay as original, so I assume wild bay is correct and will use that in favor of blood bay if it should be so.
Thank you very much for clearing that up, I'm obsessed with genetics and like to make sure I have it right.
Posted via Mobile Device

Brown is the correct term. Registries take a looooooooong time to catch up lol.

Ah, okay. I'll just drop seal bay all together then, lol. Thanks again.

I wouldn't refer to the wild bay as a blood bay as there are people/areas that use blood bay to describe the richer blood red coat that some bays have.