Sound attenuation: diminution of the intensity of sound energy propagating  in a medium. (The Free Dictionary)

Butt Glazing: a glass installation technique that does not use mullions for vertical edge support of the glass. (Homewyse)

Grandfathered: exempt from a new law or regulation. (The Free Dictionary)

Vent Stack: a pipe placed vertically or nearly so and connected to the traps of plumbing fixtures in such a manner as to ventilate them and prevent the water seal from being siphoned out of them. (Merriam Webster Dictionary)