monopsony
A market situation in which there is only one buyer for a product.
Our next task is to consider the change in the amount of a commodity purchased when the market changes from an indefinitely large number of competing buyers to a single buying agency. This may be described as the comparison between competitive and monopsony buying, just as the corresponding comparison for selling was called the comparison between competitive and monopoly output.
A buyer with disproportionate power.
The result is different when the resource buyer is a monopsony. The monopsony firm is a single buyer, and therefore it faces the market supply curve.
Where it comes from
From Ancient Greek μόνος (mónos, “alone, solitary; singular, unique”) + ὀψωνέω (opsōnéō, “to buy fish or victuals in general”) + -y, modelled after monopoly. ὀψωνέω is from ὄψον (ópson, “delicacies”) + ὠνέομαι (ōnéomai, “to buy, purchase”). The English word was coined by British classics scholar Bertrand Hallward (1901–2003), and popularized by British economist Joan Robinson (1903–1983) in her book The Economics of Imperfect Competition (1933): see the quotation.
Adapted from the Wiktionary entry monopsony (CC BY-SA 4.0).