Safely remove or Eject??

Can anyone let me know what the difference between these two is please?

I am aware of the discussion regarding IF USB devices do or don't 'need' to be safely removed but wondered how 'ejecting' differed?


Also, is it true that SD cards don't require safely removing or ejecting at all?

How do these things differ, if at all?
Portable HDDs, USB sticks, SD cards etc..


Cheers! :)