@Background Pony #91Z0
Welcome to the internet, you must be new here.
“Anthro” is the common abbreviation for “antropomorphic animal”, although strictly speaking antropomorphism can apply to anything that’s not already human to begin with. Most anthros are animal-based though.
Furries are an adjacent term to
anthro, but not totally interchangeable–the former refers to a specific subculture and its conventions and tropes are not the end-all be-all of the wider spectrum of anthro.
The degree of antropomorphisation varies greatly. At the low end of the scale we have animals with human-like, but distinctly non-human intellect and cultures (e.g. Watership Down), animals that emote like humans (e.g. the horses in Spirit, Stallion of the Cimarron), animals that are fully animal-shaped but have human-like inner lives and culture (e.g. Lion King), and animals that on top of that also do “people things” such as wear human clothes, have human technology, while retaining a very animalistic anatomy (e.g. Peter Rabbit).
MLP features a universe of ponies that are already rather anthropomorphised with their emotes, gestures, inner lives and society, and brought closer to human anatomy in the face region. This is the baseline for the tagging definitions on Derpibooru. When we say “pony” we mean an MLP, low degree anthro pony; not the Equus ferus caballus of our own world. For characters rendered closer to the non-antropomorphised end of the human-anthro-animal spectrum, we have tags like “hoers” and “realistic anatomy”. Probably others as well, but this is already turning out a big ole post.
For Derpibooru purposes, “pony” characters are quadrupedal, but for the sake of cartooning or gags do occasionally stand bipedally for short periods.
Then, a “semi-anthro” is generally shaped just like a “pony”, but are bipedal. Since they tend to carry things with their forelegs and be posed like humans, “semi-anthros” often have somewhat altered limb anatomy, bringing the elbows and knees closer to the halfway point on each leg.
Once a character’s anatomy departs from “pony” more than the small adjustments in limp proportions for “semi-anthro”, i.e. has clear elements of human anatomy, we tag “anthro”. This is probably the widest scope, as it ranges from slightly elongated “semi-anthro” all the way to pony-coloured humans with sorta ponyish heads.
An “equestria girl” is otherwise human, but has pony colours.
A “human” generally has no discernible non-human anatomy, however the category does allow for non-human peripheral, “accessory” anatomy such as animal ears, tails, and fantastic elements like wings and horns. If these are included on a “human”, that is to be tagged accordingly. In this sense, Derpibooru tagging considers “kemonomimi” a subclass of “human”.
On the scale below, 1 is “pony”, 2 is “semi-anthro”, 3 and 4 are “anthro”, and 5 is “human”.