[akritrime]

There are two things. First, a distributed exchange can be built around an AMM, so match making is essentially lazy because you are selling into and buying from an automated liquidity pool, instead of depending on market makers and matching orders. Second, there are order book based protocols that implement order matching as a decentralized consensus mechanism. So the blockchain itself can be a matching engine, provided that's what it's execution environment is built to do.

Underlying all the buzzwords, blockchains are about distributed communications with economic incentives attached to them and a more complex leader election mechanism. So there can be many things that can have the term blockchain slapped on them with a bit of tweaking.