Why did Palpatine pick 'Vader' as a name for Anakin?

Question

When Anakin turned to the Dark Side Darth Sidious obviously saw fit to give him a new name:

PALPATINE: Henceforth you shall be known as Darth...Vader.

ANAKIN: Thank you, my master.

I've seen the question that's already been asked about the out-of-universe reason why George Lucas landed on the name Vader. I'm interested in whether there's an in-universe explanation for why Palpatine decided to call him what he did.

Was it just a random name plucked out of thin air? Did Palpatine pick it because he knew that Padmé was shortly due to give birth? Is there any preexisting connection between the name 'Vader' and the Dark Side of the Force?

Answer 1

Per the Matthew Stover novelization, the name "Vader" was plucked from the Force itself (emphasis mine):

Darth Sidious laid a pale hand on Anakin's brow. "Then it is done. You are now one with the Order of the Dark Lords of the Sith. From this day forward, the truth of you, my apprentice, now and forevermore, will be Darth ..."

A pause; a questioning in the Force - An answer, dark as the gap between galaxies - He heard Sidious say it: his new name.

Vader.

^{Revenge of the Sith: The Official Novelization Chapter 17: "The Face of the Dark"}

But there's no indication of what it means, or why the Force chose it for him.

Answer 2

I personally thought Sidious picked the name as a subtle mockery of Anakin. Sidious is the only one who knows that Anakin and Padme were married, so theres a good chance he probably knew she was pregnant too. Plus Palpatine worked along side Padme for years while she was Queen and he was a senator. He probably suspected something at a certain point. According to another comment, the force "revealed" the name to Sidious, and its not like the force isn't all-knowing so the name just naturally fit Anakin's situation. As it was her specific death in childbirth that is the inciting incident to him becoming a sith. So does work out rather well.