They are applications that run on decentralized network
for example YouTube: when we request any video or any data we are actually requesting all these data from one single source which is YouTube server
In a decentralized application actually it runs on thousands of servers and they call it nodes.
that’s the power of Dapps by having thousands of servers will never go down unlike centralized apps which can go down at any time.
In centralized apps we as the users pay money on subscriptions or by watching ads.
In the decentralized world actually is the opposite, you get paid by watching and consuming content, another reason decentralized apps became very popular is because there is no censorship, no personalization or blocking some country’s users ..all users are equal.