Darkwave is synth oriented goth rock. It bends more towards Gary Numan & John Carpenter eccentric sounding flavors. You could make an argument for Skinny Puppy being darkwave I suppose. Probably used to describe a lot of Germanic club scene music and has some basis on Kraut rock like Kraftwerk.
Here's one of TJ's favorites.
https://www.youtube.com/watch?v=2Ds3ADeXSFI