1. (roofing) A method of asphalt shingle application, whereby shingle courses are applied vertically, up the roof rather than laterally across and up.
2. (nautical) spun yarn used in racking ropes
3. (brewing) The process of clarifying, and thereby deterring further fermentation of, beer, wine or cider by draining or siphoning it from the dregs.
1. present participle of rack