...
A contract is a collection of code (its functions) and data (its state) that resides at a specific address on the Ethereum blockchain. Contract accounts are able to pass messages between themselves as well as doing practically Turing complete computation.
A smart contract is a mechanism involving digital assets and two or more parties, where some or all of the parties put assets in and assets are automatically redistributed among those parties according to a formula based on certain data that is not known at the time the contract is initiated.
The key property of a smart contract is simple: there is only a fixed number of parties.
Decentralized applications
A decentralized application is similar to a smart contract, but different in two key ways:
- a decentralized application has an unbounded number of participants on all sides of the market.
- decentralized application need not be necessarily financial
Decentralized organizations
In general, a human organization can be defined as combination of two things:
- a set of property
- a protocol for a set of individuals
The idea of a decentralized organization takes the same concept of an organization, and decentralizes it. Instead of a hierarchical structure managed by a set of humans interacting in person and controlling property via the legal system, a decentralized organization involves a set of humans interacting with each other according to a protocol specified in code, and enforced on the blockchain
Solidity, Serpent, LLL
Contracts live on the blockchain in a Ethereum-specific binary format called Ethereum Virtual Machine (EVM) bytecode. Contracts are typically written in some high level language such as Solidity and then compiled into bytecode to be uploaded on the blockchain. There are some high-level languages and compilers to generate this bytecode:
...
https://klmoney.wordpress.com/