from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A stock-market condition wherein two rival buyers exert a controlling influence on numerous sellers.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An economic condition in which a two number of buyers exert control over the market price of a commodity.
duo- + Greek opsōniā, purchasing of provisions (from opsōnein, to buy food : opson, cooked food); + ōnē, buying from ōneisthai, to buy.(American Heritage® Dictionary of the English Language, Fourth Edition)
By analogy with monopsony based on Greek δυο (dyo, "two") + ὀψωνία (opsōnia, "purchase"). (Wiktionary)