A stock market, equity market or share market is the aggregation of buyers and sellers (a loose network of economic transactions, not a physical facility or discrete entity) of stocks (also called shares), which represent ownership claims on businesses; these may include securities listed on a public stock exchange as well as those only traded ...
Redundancy is a system design in which a component is duplicated so if it fails there will be a backup. Redundancy has a negative connotation when the duplication is unnecessary or is simply the result of poor planning.
The registry is the most essential part of your computer since it stores all essential settings and programs that enable your computer to operate smoothly. However, over a period of time the registry accumulates redundant files or entries that tend to clog it and affect its smooth running.