The legal term for Piracy will change over time due to politicians wanting to use it to portray an agenda. In this case the agenda that copyright infringement is some kind of evil act. (I agree it is)

But this agenda is set by lobbyists paying governments.

But the use of the original term is not as far away as we would like to beleave.

The whole idea of plundering ships at sea was not looked on negatively by the British government. It was indeed encouraged.

What was illegal was doing so without a privateering "Licence" from the government and paying the government their share for doing it.

So Piracy is not plundering goods. It is plundering goods without a licence.

Still.

"Avast me hearties give us all your swag"

EDIT: Of course the British only wanted to licence people doing it to enemy ships.