Decentralized applications also known as dApps are a new type of technology that can make use of blockchain. dApps can be used in any type of industry, they are structured to ensure transparency.
The dApps can be used in a number of ways and can revolutionize anything that they are used for. If driverless cars could refuel and engage in ride-sharing schemes without human oversight, residents could trade energy generated through solar panels automatically amongst each other, we could seamlessly authenticate medical supplies sent abroad for aid relief, a platform where users can reward content curators for their creative contributions, a world where information is not held in the hands of private companies and the services which the general public can control not private parties.
All this world of possibilities is made possible with dApps.
dApps are essentially software you can manage with your community. This means that when you use it you are not lending your personal data over to a faceless company who may misuse it.
In the world of cryptocurrency you can use a dApp to execute a number of smart contracts so that people around you with data can lend or sell the data to you. The dApp would be the interface you would use to ask and pay for your data. 
A dApp exists as a decentralized network run by users with no central control or single point of failure. This means they are open source and the whole community is open to contribute as such there needs to be consensus.
For example–Wikipedia where all the contributors have to agree on whether Freddie Mercury was from India or not or whether a Caesar salad was invented in 1924 or in ancient Rome?
Although Ethereum is often mistakenly described as a cryptocurrency is actually a platform for building dApps amongst other things with a native token called Ether. dApps works autonomously once launched. The users vote on any changes to the software using a consensus mechanism. They provide the computing power necessary to keep the network running and receive tokens native to that platform as compensation.
So how do dApps compare to smart contracts? Will they work hand in hand? A dApp uses smart contracts to run. Think of a smart contract like a sentence dApp is like a story. The sentence makes sense on its own but work stronger when it’s part of a story they work hand in hand.
