Osmosis 



The diffusion of a solvent (especially water) across a dif- 

 ferentially permeable membrane separating two solutions or 

 separating a solution and a solvent. 



Osmotic Concentration 



The concentration of salts in a solution. 



Osmotic Pressure (of a Solution) 



The rating or index of potential maximum pressure 

 which can develop in a given solution when it is exposed to 

 Osmosis. 



Osteology 



The study of the development and nature of bones in 

 vertebrate animals. 



Oued 



A valley that contains water in rainy seasons (Arabian). 



Outbreak 



The occurrence of an organism in large numbers or in 

 sufficient number to cause serious damage over an appreci- 

 able area. 



Outbreeding 



The mating of individuals that are not closely related, 

 cf. Inbreeding. 



Outcrop 



A geological stratum that is exposed on the surface of 

 the earth. 



Outwash, Glacial 



Material carried by streams of melt water from a glacier 

 and deposited in the form of plains, deltas, and Valley 

 trains. 



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