Distributed contracts or Crypto Contracts also called Smart Contracts. To work with Ethereum contracts you can use npm packages like solc to compile solidity and use the Web3 Package for sending the contract to the Ethereum node via http rpc or Ipc socket.
Examples of Smart Contracts written in Solidity:
Some general knowledge
What cryptographic contracts have to do with legal contracts? Nothing. Smart contracts are dumb scripts.
Quote
Coming from a #legalhacker background these “things” are clearly neither smart (indeed their logic capabilities have only recently reached turing complete capacity), nor are they contracts (they are, afterall, just scripts) - Casey Kuhlman 
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But because of the name "contract" they often get confused. I actually met a blockchain consultant once who mixed up cryptocontracts and timestamping hash of the file into a blockchain.
One way of thinking about smart contracts, and the way we’re going to think about them here, is as extremely basic, stateless web-services. Webservices are units of functionality in a system (the internet), with a well defined API and an identifier (IP address) that can be used to call them. Similarly, a smart contract is a unit of functionality, the public functions exposed by their Solidity contracts is the API, and their public address is the identifier. A web-service is normally called by making an http request, and a contract is called by making a transaction. Also, in most cases everyone is allowed to call them the endpoints are exposed to the public, so security must be handled on a call-by-call basis, and the same thing goes for contracts and their functions. We can even utilize common patterns and architectures, such as for example the microservices architecture - Andreas Olofsson
History
The phrase "smart contracts" was coined by computer scientist Nick Szabo
According to Wikipedia Smart contracts are computer protocols that facilitate, verify, or enforce the negotiation or performance of a contract, or that obviate the need for a contractual clause. Smart contracts usually also have a user interface and often emulate the logic of contractual clauses. Proponents of smart contracts claim that many kinds of contractual clauses may thus be made partially or fully self-executing, self-enforcing, or both. Smart contracts aim to provide security superior to traditional contract law and to reduce other transaction costs associated with contracting -
Contracts can be used for:
- Smart Stock
- Self-enforcing derivatives
- Trustless letters of credit
- Proof of existence
As well as Smart Property
- Smart Digital Property
- Smart Physical Property