or vernier caliper Instrument for making very accurate linear or angular measurements. Introduced in 1631 by Pierre Vernier ( 1580-1637), it uses two graduated scales: a main scale similar to that on a ruler, and a specially graduated scale, the vernier, that slides parallel to the main scale and enables readings to be made to a fraction of a division on the main scale
{i} Vernier scale, short graduated scale that measures fractions of divisions on fixed scale; device that provides a tool with a higher level of accuracy (Machinery)
A short scale made to slide along the divisions of a graduated instrument, as the limb of a sextant, or the scale of a barometer, for indicating parts of divisions
It is so graduated that a certain convenient number of its divisions are just equal to a certain number, either one less or one more, of the divisions of the instrument, so that parts of a division are determined by observing what line on the vernier coincides with a line on the instrument