1. (n.) The act of depleting or emptying.

2. (n.) the act or process of diminishing the quantity of fluid in the vessels by bloodletting or otherwise; also excessive evacuation, as in severe diarrhea.

ablation absorption assimilation attrition burning up cleaning out clearance clearing consumption corrosion curtailment cut cutting decrease decrement defecation deliquescence depreciation derogation detraction digestion diminution dip discharging cargo disparagement dissipation dissolution drain drainage draining eating up egress elimination emptying erosion evacuation evaporation excretion exhausting exhaustion expending expenditure extraction finishing impairment impoverishment ingestion leakage lessening loss off-loading reduction remission removal retraction retrenchment shortening shrinkage spending squandering truncation unloading using using up venting voidance voiding wastage waste wastefulness wasting away wear and tear wearing wearing away wearing down