The phrase "command key" refers to a specific button or set of buttons on a computer keyboard that is used to perform special functions or commands. Full definition
The voice command key also acts as a bottom side key for unlocking the external display. (cnet.com)
On the left spine are the voice command key, the volume rocker, a red key, and a 2.5 mm headset jack. (cnet.com)
Software keys allows for users to reconfigure the location of the back button, change the look and style of the bar, and even add in additional dedicated command keys for extra functions. (androidauthority.com)