Why are those long planks of wood called “2 by 4s”?

What units are we measuring here? 2 what by 4 what? Regardless of what units were using the proportions seem all off. 2 by 4 seems to imply that its a rectangle where the longer side is twice the side of the shorter side, but that doesn’t describe this wood size at all. The long side is quite a big longer than twice the side of the shorter size. So I’m confused. Then there are other sizes of wood, like 2 by 6s, and I see similar issues there too.

Someone please explain what’s going on here.

  • Brkdncr@lemmy.world
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    7 hours ago

    Inspector came to look at the house for some reason and was impressed to see a house built in the 50’s with a giant length of walnut(?) something like 8”x 12” by 20’

    I have an old house on my property that has a similar piece of wood holding everything up.

    They don’t/can’t build like that anymore.