I am quite new to arduino .Something in the specification list makes me confused :

![enter image description here](https://i.stack.imgur.com/eMhUO.png)

I am confused about the following :

1. Input Voltage(recommended)7-12V
2. Input Voltage (limits) 6-20V
3. Operating Voltage : 5V

Is **Operating Voltage** is the voltage that is used to power up the board ?
If So,What does **Input Voltage**(recommended) and (limits) refer to? Are they regular analog input voltages?

Any Help regarding "**Operating Voltage"** and **"Input Voltage**" is highly appreciated !