| Word | Description |
| Off-grid domestic photovoltaic power system | System installed in households and villages that are not connected to the utility grid. Usually, a means to store electricity is used (most commonly lead-acid battery). Also said "stand-alone photovoltaic power system". |
| Open-circuit voltage (Voc) | The voltage across a photovoltaic cell or module in sunlight when no current is flowing; the maximum possible voltage. Unit: V. |
