How’s this for a simple definition of Ethereum in today’s New York Times:
“Ethereum is a global computing network operating according to rules defined by Ethereum software.”
Maybe that’s a little too simple.
But the article follows that up with a description giving you a better feel for it, which is “a global smartphone that can be programmed to operate according to the apps built on top of it.”
If you want to jump into the deep end of the genesis of Ethereum, I highly recommend this Wired piece titled “The Uncanny Mind that Built Ethereum,” profiling its founder Vitalk Buterin.
It has a really straightforward description of the blockchain and Bitcoin, which was to remove third parties from both the creation and transfer of currency. This was accomplished by recording payments (Bitcoin) on a new type of open ledger (blockchain).
The success of the Bitcoin blockchain made it obvious to Vitalik Buterin, and others, that you could use the blockchain to facilitate transactions and complex agreegments for anything (e.g., deeds to houses).
He realized the right type of blockchain network “could deliver every imaginable digital service, right out of the box,” and this idea eventually became Ethereum.
Vitalik recently spoke at Disrupt SF 2017 and this is how he described Ethereum:
Where Ethereum comes from is basically you take the idea of crypto economics and the kinds of economic incentives that keeps things like bitcoin going to create decentralized networks with memory for a whole bunch of applications.
In other words, Ethereum uses incentives in a decentralized network with shared memory to run diverse applications. Pretty simple.