When Gregg Easterbrook in his admittedly oversimplified description of modern Arabian psychology (The Progress Paradox , pg. 141) said "Americans asserted suzerainty over much of Islam's oil wealth," he sent me on a journey, as the folks from Raleigh County, GA say, "all the way to Egery and back."
The dictionary definition of 'suzerainty' refers one on to the word 'suzerain.'
A suzerain is a sovereign, either an individual or state, holding political control over another state, thus a dependent state. Historically, a suzerain was a feudal overlord.
Somehow that left me a little confused still about Easterbrook's use of the term. So I turned to Wikipedia to read up on 'suzerainty.' Wikipedia says that 'suzerainty' refers to a relationship between a superior and subordinate for which there are no accurate contemporary examples. The accurate use of the word, I gathered, refers to the relationship between a feudal lord and his vassals.
Before I realized what I'd done, I was reading up on the etiology of the word 'suzerain,' feudalism as a concept, feudal law, the history of OPEC and more generally the history of the petroleum industry in the Arabian peninsula and heaven knows what else!
So, guess what. I now have a fairly good idea where the word came from, why the word was coined in about 1600, how it was intended to distinguish a very specific relationship of reciprocal obligations between two political entities and how that relationship, if it every really existed, wasn't named or defined until it had ceased to exist. And I know the word is being used today in a very loose and unclear fashion to refer to various power relationships; the word tells us nothing about the nature, source or practices associated with the so named power relationship.
That said, nowadays the word 'suzerain' means 'overlord' and the word 'suzerainty' can be taken to mean 'overlordship' or the position of an overlord.
Chase done; there we go.