Application-specific blockchains, such as Gateway, are blockchains customized to operate a single application. Instead of building a decentralized application on top of an underlying blockchain like Ethereum, developers build their own blockchain from the ground up which is usually meant just for a singular application – but one that can be continually upgraded to met user needs.
Source: https://www.coindesk.com/tech/2023/07/21/wormhole-launches-new-bridge-connecting-to-any-cosmos-appchain/?utm_medium=referral&utm_source=rss&utm_campaign=headlines