Eh, I don't even think it's more abstract. Like if you're in intro engineering/physics math, and you have R^3 with unit vectors i,j,k, and R^2 with unit vectors I,J, then a function f: R^3 -> R^2 is linear exactly when you can calculate all f(v) = f(ai + bj + ck) = af(i) + bf(j) + cf(k). Then you can define f by "what is f(i)? (Some AI+BJ). What is f(j)? (Some CI+DJ). What is f(k)? (Some EI+FJ)", and then a matrix is just a tabulation of those things. Basically, linear functions let you pick out just n points to define them everywhere, kind of like polynomials. Matrices are that information. Perfectly concrete even at the super intro level. Matrix "multiplication" becomes automatic and trivial; it's just function composition tabulated.
Actually it seems way more concrete to me than mystery rules for "multiplying" arrays.
Actually it seems way more concrete to me than mystery rules for "multiplying" arrays.