The matching game pelmanism.
The proportion of a substance in a whole.
The act, process or product of reducing the volume of a liquid, as by evaporation.
The act or process of removing the dress of ore and of reducing the valuable part to smaller compass, as by currents of air or water.
The direction of attention to a specific object.
A field or course of study on which one focuses, especially as a student in a college or university.
The amount of solute in a solution measured in suitable units (e.g., parts per million (ppm))
A memory card game in which a pack of cards is spread out face-down and players try to turn up pairs with the same symbol.
A system of training to improve the memory.