n 1  :  the act or process of perspiring  2  :  a saline fluid that is secreted by the sweat glands, that consists chiefly of water containing sodium chloride and other salts, nitrogenous substances (as urea), carbon dioxide, and other solutes, and that serves both as a means of excretion and as a regulator of body temperature through the cooling effect of its evaporation .
 
 
 
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