Buyers and sellers market are the terms used in context of economics and knowledge of these terms is very important because if company has an idea which marketplace it is one can decide about the strategy for selling its products.
Buyers markets are those where the price for a particular product is falling and there are more sellers in market than buyers which in turn give purchaser of product an edge over vendor. It can also be used in context of stock market when there is panic among investors and they began selling stocks at throwaway prices.
Sellers markets refers to those where there are many buyers but not many sellers leading to rise in price and therefore sometimes it may lead to monopoly as demand is more than supply. Hence if a company manufactures such products they can raise the price without worrying about the demand for that product.