zero scale (of an analog-to-digital converter [a digital-to-analog converter] with true zero)

A term used to refer a characteristic to the step whose nominal midstep [step] value equals zero.

NOTE 1 The subscript for the letter symbol of a characteristic at zero scale is "ZS".

NOTE 2 In place of a letter symbol, the abbreviation "ZS" is commonly used.

References: 

JESD99B, 5/07