I’m now envisioning a car wrecking its way into a house, and then trying to make cat sounds with its engine and stuff (the meows would be kinda hard, but whining would be easy enough) at the door of the restroom, and then the tires just squeal as it zooms away as the person opens the restroom door. I’m envisioning the sheer, overwhelming perplexity on their face.

I’m completely cracking up over this image. It’s amazing.

That is an excellent point. Yeah, PSI would totally read as pounds times square inches which would be something else entirely. Adding in the extra P would fix it, too. PPSI. Suppose it’s another thing that people just have to get used to, haha.

Because in^2 is generally said “square inches.”

So it’s “pounds per square inch.”

Sometimes “per” will get its own letter, like in PPM - parts per million - and sometimes it’s left off, as in PSI.