Delta is the initial letter of the Greek word διαφορά diaphorá, "difference".  The word Delta is often used in the Land Surveying profession when describing the difference in values between two measured points. 
The closer these values are to the number Zero, the more favorable the outcome becomes. In our calculations, measurements, instruments and work ethic we strive for the highest degree of accuracy and precision. 
       We want to see Delta Zero.