I think what they mean is still a mathematical meaning, just a separate definition of ‘divisible’ not limited to integers. The term is usually used for the set of integers, but really you could define it on any set.

“For x,y in S, x is called divisible by y if and only if x/y lies in S.” could be such a definition. Obviously you also need a definition of “/”, which is usually x/y=a <=> a*y=x with any operation *. This usually involves an algebraic Ring.