Reusing a function C in functions A and B makes A and B dependent on C. If the definition of C changes, the definitions of A and B also change.

So this is more than reusing some lines of code. It's a statement that you want A and B to change automatically whenever C changes.

If this dependency is introduced purely out of a desire to reuse the lines of code that make up C, then I'm calling it compression. In my view, this is a bad and misleading form of abstraction if you can call it that at all.