Good question. It's interesting that we also use the word in the sense of a profit or return on an investment (e.g., "equity in your home"). I take that as a

Good question. It's interesting that we also use the word in the sense of a profit or return on an investment (e.g., "equity in your home"). I take that as a nod to its former meaning of "justly conducted," since without proper methods (in that sense "fair") business accounting would be impossible.