Sentence:  A single buyer in a factor market is known as a <WSD>monopsony</WSD>. Some economists refer to a <WSD>monopsony</WSD> as a "buyer's monopoly." A monopoly is a single seller of a product; a <WSD>monopsony</WSD> is a single buyer of a factor. 
Meaning of the word marked with <WSD> tags:  A buyer with disproportionate power.