It means an integrated electric energy (consumption) while an external input (contact input) is ON.
It is a measurement element different from the electric energy.
It is measurable using below device:

1. EcoMonitorLight
High Performance Model (Model: EMU4-HD1-MB)

2. EcoMonitorPlus
Energy Measuring High Performance Model (Model: EMU4-HM1-MB)
Energy Measuring Extension Model for Same Voltage System (Model: EMU4-A2)
Energy Measuring Extension Model for Different Voltage System (Model: EMU4-VA2)