Noun. One of two forces that cause breasts to slowly sag towards the floor. Along with gravity, the force of grabity causes a constant pulling, rubbing, tugging and stretching of the breasts. The force is propotional to the sensitivity of the breasts and the attractiveness of their owner and increases exponentially in the presence of horny, attractive men.
If it weren't for the force of grabity I'd still have a "B" cup.
A Shackteau is a humble, weather-beaten, structurally questionable shelter located in a spectacular or highly coveted place—Wales, Jackson Hole, Sun Valley, Crested Butte, coastal Maine, the Alps—where the building itself may be worth almost nothing, but the dirt, view, access, and mythology make it absurdly valuable.
In use:
Shackteâu - We thought it was an abandoned shed until the realtor called it a rare alpine Shackteâu with unobstructed views and listed it for $2million.