Chart of Accounts
Definition
The list of categories your bookkeeping uses to organize every transaction. A well-built chart of accounts is what turns raw transactions into reports you can make decisions with.
Want a deeper explanation?
Your chart of accounts decides what questions your reports can answer. If marketplace fees, fulfillment and ad spend are lumped together, you cannot see which one is eating your margin.
For e-commerce, it should separate product costs, selling costs by type and overhead, and ideally allow reporting by channel. Watch for: large catch-all accounts like "Miscellaneous" or "Ask my accountant", which hide the details you need.
Example
Splitting "Shipping" into inbound freight (part of COGS) and outbound fulfillment (a selling cost) lets you see true gross and contribution margin.