Micrometer

n. instrument for microscopic or tiny measurements

For the unit of length, see micrometre A micrometer, also known as a micrometer screw gauge, is a widely used device in mechanical engineering for precisely measuring thickness of blocks, outer and inner diameters of shafts and depths of slots. Appearing frequently in metrology, the study of measurement, micrometers have several advantages over other types of measuring instruments like the vernier caliper.
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Noun
1. caliper for measuring small distances
(synonym) micrometer gauge, micrometer caliper
(hypernym) caliper, calipers, calliper, callipers
2. a metric unit of length equal to one millionth of a meter
(synonym) micron
(hypernym) metric linear unit
(part-holonym) millimeter, millimetre, mm
(part-meronym) nanometer, nanometre, nm, millimicron, micromillimeter, micromillimetre

n. micrometer, calliper

(n.)
An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given directly is that of the image of the object formed at the focus of the object glass.