In its simplest form, Ethereum is an open software platform based on blockchain technology that allows computer software developers to create and deploy decentralized applications.

Ethereum is the foundation of a new internet age:

• An internet integrated into money and payments.
• An internet where users can own their personal data and users’ apps do not steal from them.
• An internet where everyone has access to an open financial system.
• An internet built on a neutral, open access infrastructure that is not controlled by any company or individual.

All transactions we make on the internet (shopping, banking transactions, our use of social media, our internet history, etc.) are recorded in data banks. The purposes for which this information is used and stored is completely ambiguous to the user. 

The Ethereum project whitepaper, published by Vitalik Buterin in 2013, defines an open source platform that can work with smart contracts that is transparently visible to anyone. New applications (dApp) developed on the Ethereum platform can prevent information such as personal data from being stored and used for different purposes by third parties. With its decentralized structure, Ethereum processes these transactions on many different devices allowing it to be anonymous and distributed. Ethereum eliminates the need for software developers to recreate their own blockchains for applications written through smart contracts, and provides the opportunity to benefit from security and decentralization for all applications integrated on it.

For more information:

https://academy.binance.com/tr/articles/what-is-ethereum