Ethereum is an open-source, public, blockchain-based distributed computing platform and operating system featuring smart contract (scripting) functionality. It supports a modified version of Nakamoto consensus via transaction-based state transitions.
Ether is a cryptocurrency whose blockchain is generated by the Ethereum platform. Ether can be transferred between accounts and used to compensate participant mining nodes for computations performed. Ethereum provides a decentralized virtual machine, the Ethereum Virtual Machine (EVM), which can execute scripts using an international network of public nodes. The virtual machine's instruction set, in contrast to others like Bitcoin Script, is thought to be Turing-complete. "Gas", an internal transaction pricing mechanism, is used to mitigate spam and allocate resources on the network.
Ethereum was proposed in late 2013 by Vitalik Buterin, a cryptocurrency researcher and programmer. Development was funded by an online crowdsale that took place between July and August 2014.
Hyperledger (or the Hyperledger project) is an umbrella project of open source blockchains and related tools, started in December 2015 by the Linux Foundation and supported by big industry players like IBM, Intel and SAP to support the collaborative development of blockchain-based distributed ledgers.
Hyperledger is a permissioned blockchain infrastructure, originally contributed by IBM and Digital Asset, providing a modular architecture with a delineation of roles between the nodes in the infrastructure, execution of Smart Contracts (called "chaincode" in Fabric) and configurable consensus and membership services. A Fabric Network comprises "Peer nodes", which execute chaincode, access ledger data, endorse transactions and interface with applications. "Orderer nodes" which ensure the consistency of the blockchain and deliver the endorsed transactions to the peers of the network, and MSP services, generally implemented as a Certificate Authority, managing X.509 certificates which are used to authenticate member identity and roles.