Drift
a word of several applications. 1. Architecture: The push, shoot, or DRILL horizontal thrust of an arch or vault on the abutments. 2. Geology: A loose aggregation or accumulation of transported transported matter matter, consisting of sand and clay, with a mixture of angular and rounded fragments of rock, some of large size having occasionally one or more of their sides flattened or smoothed, or even highly polished. The smoothed surfaces usually exhibit many scratches parallel to each other, one set often crossing an older one. The drift is generally unstratified, in which case it is called till. This may be in places 50 or even 100 feet thick. 3. Ordnance: A priming-iron to clean the vent of a piece of ordnance from burning particles after each discharge. 4. Machinery: A round piece of steel, made slightly tapering and used for en larging a hole in a metallic plate by be ing driven through it. The drift may have a cutting edge merely on its advance face, or it may have spirally cut grooves which give the sides of the drift a capacity for cutting.