Definition of DOCK : the place in a criminal court where a prisoner stands or sits during trial — in the dock : on trial
Commonly used in British/Commonwealth English, and Nature is based in London. I don't think I've ever heard it used in American English.
Only criminal defendants are in the dock.
Any witness would "on the stand" including a defendant who is called as a witness.
https://en.wikipedia.org/wiki/Witness_stand https://en.wikipedia.org/wiki/Courtroom
Commonly used in British/Commonwealth English, and Nature is based in London. I don't think I've ever heard it used in American English.