A ledger is a book or record where financial information is carefully tracked and organized. Think of it like a detailed scoreboard for money: every dollar earned goes on one side, every dollar spent goes on the other, and the ledger shows exactly where you stand.

Businesses use ledgers to record every sale they make and every expense they pay, from buying supplies to paying employees. Before computers, shopkeepers kept thick leather-bound ledgers with lined pages, writing entries in neat columns with fountain pens. Today, many ledgers exist as computer files or spreadsheets, but they serve the same purpose: creating an organized record that can be checked and verified.

You might keep a simple ledger yourself to track your allowance or earnings from chores, recording what comes in and what you spend. Ships' captains keep ship's logs recording daily events and observations. Scientists keep lab notebooks documenting their experiments. In each case, a ledger creates a reliable record that others can examine to understand exactly what happened.