Generally speaking, a ledger represents a book or database in which account transactions from one or many accounts are recorded. In crypto, ledger stands for the blockchain, a distributed ledger technology.
The blockchain ledger is a decentralized database storing data on all transactions on the network in an immutable, tamper-proof, encrypted, transparent, and consensus-driven manner. Each participant within the blockchain network functions as a ledger, maintaining records of all transactions in the peer-to-peer network.
Ledger is also a company that is a leading provider of hardware wallets where users can store their cryptocurrencies in a highly secure manner. Two popular products crypto investors use worldwide are the Ledger Nano X and the Ledger Nano S, which support secure storage for hundreds of digital assets.