1) Analytical chemistry 
A Stock Solution is a concentrated solution that will be diluted to some lower concentrated for actual use. Stock solutions are used to save preparation time, conserve materials, reduce storage space, and improve the accuracy with which working lower concentration solutions are prepared. In chemistry, a stock solution is a large volume of a common...
A concentrated chemical solution that is diluted before use
A concentrated chemical solution that is diluted before use. 
a concentrated chemical solution, diluted before using.