| Customer | A customer in LedgerUp. A customer can have multiple usage accounts. |
| Account | An account that owns grants and usage. You can link it to a LedgerUp billing customer and retrieve aggregated usage for a date range. |
| Metric | A company-wide definition of measured usage within a namespace. Usage events reference these shared metrics. |
| Grant | An amount allocated to an account for a service period. A grant can expire. |
| Refill configuration | Automatic balance refill settings for an account and metric. When active, the minimum balance is the refill threshold and the target balance is the balance to restore. |
| Usage event | A quantity of usage for an account and metric over a service period, such as phone-call minutes, credits, or seats. |
| Contract | A customer’s billing agreement. Rate cards and prices determine the final contract-line amounts. |
