How are solutions classified according to their comparative tonicity?
Comparative to another, a solution can be hypotonic (or hyposmotic), isotonic (or isosmotic) or hypertonic (or hyperosmotic). When a solution is less concentrated than another the adjective hypotonic is given and the more concentrated is called hypertonic. When two compared solutions have the same concentration both receive the adjective isotonic. So this classification makes sense only for comparison of solutions.
