effective, average, marginal. -The effective tax rate is the best measure of the tax burden because it is the average level of tax on all income from taxable and nontaxable sources. -The average tax rate measures the average level of tax on only taxable income.
Navigating the eschaton. The eschaton is something to be avoided and something to be courted. It is a virtual singularity of human consciousness marking the end of the historical epoch. In itself it is a neutral event, one to be reckoned with. It is a point of leverage for wielding the human spirit.
Esker, also spelled eskar, or eschar, a long, narrow, winding ridge composed of stratified sand and gravel deposited by a subglacial or englacial meltwater stream. Eskers may range from 16 to 160 feet (5 to 50 m) in height, from 160 to 1,600 feet (500 m) in width, and a few hundred feet to tens of miles in length. They may occur unbroken or as detached segments. The sediment is sorted according to grain size, and cross-laminations that show only one flow direction commonly occur.