wave
				   		Oscillation caused by a disturbance; as it propagates through a medium (mechanical waves) or a vacuum (electromagnetic waves), it carries energy.
				
 
					
					
					
						mean position 
						Horizontal line around which the wave oscillates, carrying energy.
				  	
 
					
						wavelength 
						Distance between two consecutive crests or troughs; it corresponds to the distance traveled by the wave over time (its period).
				  	
 
					
						displacement 
						Gap in relation to the mean position.
				  	
 
					
						crest 
						Highest point of the wave.
				  	
 
					
						trough 
						Lowest point of the wave.
				  	
 
					
						amplitude 
						Maximum displacement of a wave in relation to its mean position; it corresponds to the amount of energy transmitted.
				  	
 
					
						propagation 
						Motion of a wave leaving its source.