Smart contracts are self-executing contracts with the terms of the agreement directly written into code. They run on a blockchain network, which is a decentralized and distributed ledger technology. Smart contracts automatically execute and enforce the terms of a contract when predefined conditions are met

Truffle is a popular development framework for Ethereum blockchain. It provides a development environment, testing framework, and asset pipeline for building decentralized applications (DApps) on the Ethereum platform.

Hardhat is another popular development framework for Ethereum smart contracts and decentralized applications (DApps). It provides a wide range of features and tools for Ethereum developers, making the development and testing of smart contracts easier and more efficient.

"Ethers" generally refers to both the native cryptocurrency of the Ethereum network and a popular JavaScript library used for interacting with the Ethereum blockchain.