When we say that Solution A is hyperosmotic, or Solution A is isosmotic,
or Solution A is hyposmotic, we compare the solution A to other solutions.
These other solutions are the reference solutions: i.e. the reference points for comparison.
In Biology,
the reference solutions will be either the extracellular solutions (Blood, extracellular fluids) or the intracellular solutions.
Let's say that we work on cells.
Solution A is hyperosmotic means:
Solution A is isosmotic means:
Solution A is hyposmotic means: