Oh right, that's the proper name for it. I was reading about herb gardening last week and it came up because a lot of mint family plants have them. It's one of those things you see all the time but never know there's a specific term for it. Makes sense when you think about it, square stems. Kind of cool how common plants have these little details.
Had me in the first half thinking this was gonna be some weird pickup line but @daniel140 is right, it's a real thing with mint plants. Never really noticed it before but now I'm gonna be checking every stem I see.