What is Wh? How to understand the capacity of portable power station?

What is WH? How to understand the capacity of portable power station?

The general capacity is about 500Wh~600Wh

Here is another concept involved. What is Wh? It can be understood as follows:

1000Wh=1 kWh.

A 500W power rice cooker,Use 500Wh outdoor power supply,Then 500Wh/500W=1 hour.