Hadouhou = Wave Motion Cannon
That's what they called it in the Star Blazers dub, so it's an accurate translation.![]()
It's not often that Japanese can translate so directly into English like this, but it works.
Ha/nami = wave (thus "tsunami"; tidal wave)
Dou/ugo(ku) = motion, movement
Hou = cannon
Guh... awkward trying to explain this in Romaji (but alas, this board doesn't allow for Japanese script)