Definition of Additive Loop

I have thought of loops as having the operations of multiplication and left and right division. I read the D. R. Hughes article on Additive and Multiplicative Loops of Planar Ternary Rings and it contains:

"We define addition in R by a + b = F(1, a, b), and multiplication by ab = F(a, b, 0). Then the set R, under addition, forms a loop with 'identity' 0, and the set R* of nonzero elements of F, under multi-plication, forms a loop with identity 1...These loops are called the additive and multiplicative loops, respectively."

The article seems to build a ring from the loops and a set with multiplication and addition defined for it fits with my understanding of rings. I have searched for "additive loop" and found it used in many articles though none have clarified my understanding of the term "loop" as addition relates to it.

A loop is a set with some binary operation on it which satisfies some axioms. That binary operation is usually called "multiplication" but that's just a name. In particular, it's perfectly fine to instead call it "addition" if that makes sense in a certain context. So, that's all that's going on here: there is an operation called "addition" on the set $$R$$ and we're using it as the operation for a loop structure on $$R$$. We then refer to this loop as the "additive loop" of $$R$$ to distinguish it from other loop structures we might have relating to $$R$$.