A blockchain is a type of distributed ledger. But new distributed ledgers are emerging. These are databases where control over the data’s evolution is shared between entities. Here’s a handy cheatsheet.
I have noticed a great deal of confusion when people talk about “Hyperledger”. I recently gave a talk about this at a meetup hosted in Paypal’s offices in Singapore. This article summarises the talk.
Hyperledger is a project, not a technology, and you don’t build stuff on Hyperledger.
When people ask, “What is Hyperledger?”, the answer I give is usually “Do you mean the project called Hyperledger run by The Linux Foundation, or do you mean one of the ledger technologies incubated by that project which used to be confusingly called Hyperledger Fabric?”. The first is a group of people, the second other is a bunch of code.