Construction terms' strange origins revealed

What do the words nipple, flashing, chase and butt have in common?

That’s right — they’re all parts of a building.

Having gotten used to casually tossing off the many quirky terms found in building construction, I’m sometimes caught short by the sidelong glances of my clients, who aren’t always sure what kind of anatomy I’m invoking.

I suspect that most of these terms harken from Middle Ages-era builders who, like their modern counterparts, delighted in coining colorful or even risqu