Screws in Japanese
To further complicate matters, a 'flathead' is also known by many names in English. Did you know it is also called ’slotted’ or ’straight’? Or how about Standard, Regular, or Flat tip? Far too many names for an instrument that makes it easy to slip and scar the walls. “Do you have a slotted screwdriver?” “No, but I have a flathead.”
At least with language, Japanese comes to the rescue.
I suggest we follow the Japanese lead. I believe, in the movie Mr. Baseball (Tom Selleck) the leading lady said something to the effect of “The Japanese take the best of the world and make it their own.” At least in the case of screws, they make it better. Observe:
プラス and マイナス
マイナス mainasu Flathead (which conveniently looks like a minus sign!)
プラス purasu Phillips (which conveniently looks like a plus sign!)
This proves Japanese are good with Math.