Real Dictionary

solution
countable noun: A solution to a problem or difficult situation is a way of dealing with it so that the difficulty is removed.
countable noun: The solution to a puzzle is the answer to it.

solution in American English
the act, method, or process of solving a problem
noun: the act of solving a problem, question, etc.

solution in British English
noun: a homogeneous mixture of two or more substances in which the molecules or atoms of the substances are completely dispersed. The constituents can be solids, liquids, or gases

solution in Chemical Engineering
noun: A solution is a liquid or solid which is made by dissolving a solid, liquid, or gas in the pure liquid or solid.