Smart Contract – a code deployed on the network that allows you to send and receive money, and do other things dependent on conditions being met. For example, A will send B x amount of money on x date provided C is met.
Dapp – Decentralized Application – an app that has its back-end code as an Ethereum Smart Contract
The Flippening – a future event that may or may not happen where the market cap for Ethereum goes past that of Bitcoin and making it an incredibly valuable cryptocurrency
Gas – the measurement of the level of processing needed by the network to process transactions. A simple transaction requires little gas, for example, when you send ETH to another Ethereum wallet but the more complicated transaction, like deployment of smart contracts, needs more
Gas Price – the cost of the ether spent on each unit of gas used in a transaction. The transaction initiator will choose and then pay the price of the gas and those transactions that have higher gas prices are given priority on the network
Wei – the smallest ether denomination. 1 ether is equal to 1000000000000000000 Wei
Gwei – another ether denomination and the one that gas transactions are usually measured in. 1 ether is equal to 1000000000 Gwei
Raiden Network – a change in Ethereum protocol that is set to be enabled soon It will enable transfers across a high-speed network and is similar to the Lightning Network that is planned for Bitcoin.
MEW – MyEtherWallet – a free Ethereum wallet site
EEA – Enterprise Ethereum Alliance – a group of corporations and startups that are attempting to work out the best ways to use Ethereum
Vitalik Buterin – A co-founder of Ethereum, indeed, he is the primary one
DAO – Decentralized Autonomous Organization – a venture capital fund, investor-directed that was built on Ethereum. In 2016, the DAO was hacked to the tune of $50 million worth of DAO funds, leading to a hard fork being implemented
These are the main terms that you are likely to come across in your journey through Ethereum and cryptocurrency. There are more but way too many to list here and many that you will likely only see on rare occasions.