Solidity is a contract-oriented programming language used for developing smart contracts on the Ethereum blockchain. It is a high-level language that allows developers to write code for executing complex transactions and create decentralized applications using smart contracts. Solidity is similar to other object-oriented programming languages like C++, Java, and Python, but it is specifically designed for developing smart contracts that are executed on the Ethereum Virtual Machine (EVM). It has a simple syntax and provides a range of built-in functions and libraries for developers to use. Solidity is open source and continually evolving, with new features and improvements being added regularly by the development community.