Glossary
Block Explorer
A website that lets anyone browse the on-chain history of a blockchain — transactions, blocks, addresses, contracts, tokens, and events.
Block explorers — Etherscan, Blockchair, Solscan, Tronscan — are the search engines of public blockchains. They index every block and expose pages for each transaction, address, contract, token, and event so anyone can audit on-chain activity without running a node.
The big explorers also offer contract verification (uploading source code to be matched against deployed bytecode), token approval managers, gas trackers, and APIs. For most users they are the default interface to "see" the chain.