Definition of vast:
		
		
		(adj) :
		
		very large or wide (literally or figuratively)
		
								
				"the Sahara desert is vast."
			
			
	
		
		
		(n) :
		
		a vast space
		
								
				"1608: they have seemed to be together, though absent, shook hands, as over a vast, and embraced, as it were, from the ends of opposed winds. -- William Shakespeare, The Winter's Tale, I.i"