As this area keeps evolving and new players try to leverage some similar terms with their own meaning, it is how we see today.
I see it a bit differently. I see distributed ledger technology (DLT) a bigger term, a superset, while blockchain is one way to implementing DLT, and therefore a subset. There are many non blockchain implementations such as using DAG (IOTA, Hashgraph), or a chain pattern without a block without using block such as Corda (well, Corda is now marketing itself as blockchain). It is more to solve business problems such as trust among different business entities.
If we just focus on the term blockchain: narrowly it’s a pattern of “chain of blocks” keeping relevant data, and cryptographically protected between blocks. This is what my first paragraph is talking about. Broadly it’s either a live network in permissionless model or a consortium platform in permissioned model. Examples of the former are Bitcoin and Ethereum (mainnet) and many new comers, while the latter is like Fabric and Sawtooth. And this is also one way to categorize blockchain implementation: permissionless vs. permissioned.
If we see blockchain this way, we won’t simply say it’s just a distributed database. More importantly it provides a programmable environment such that one can create application (smart contract, or more sexy term like decentralized app) to solve some business problems. It is the business application built on top of it brings unique values to real life, while the blockchain networks (permissionless) or blockchain platforms (permissioned) make it possible.
Just my two cents.