Technical definition
The left side of an account or journal entry.
How it works
Debits increase assets, expenses and distributions and decrease liabilities, equity and revenue. The effect depends on the account type, not on whether the transaction is favorable. Total debits must equal total credits in every entry.
Everyday example
Buying equipment for cash: debit Equipment and credit Cash for the same amount.
Common pitfall
Debit does not mean negative, bad or cash outflow.