[ mahy-krom-i-ter ]
/ maɪˈkrɒm ɪ tər /


any of various devices for measuring minute distances, angles, etc., as in connection with a telescope or microscope.
Also called mike. micrometer caliper. a precision instrument with a spindle moved by a finely threaded screw, for the measurement of thicknesses and short lengths, commonly used by machinists for turning shafts or boring holes.
Also especially British, mi·crom·e·tre.

Origin of micrometer

First recorded in 1660–70; micro- + -meter
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for micrometre (1 of 2)

/ (ˈmaɪkrəʊˌmiːtə) /


a unit of length equal to 10 –6 metreSymbol: μm Former name: micron

British Dictionary definitions for micrometre (2 of 2)

/ (maɪˈkrɒmɪtə) /


any of various instruments or devices for the accurate measurement of distances or angles
Also called: micrometer gauge, micrometer calliper a type of gauge for the accurate measurement of small distances, thicknesses, diameters, etc. The gap between its measuring faces is adjusted by a fine screw, the rotation of the screw giving a sensitive measure of the distance moved by the face

Derived forms of micrometer

micrometry, nounmicrometric (ˌmaɪkrəʊˈmɛtrɪk) or micrometrical, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for micrometre (1 of 2)

[ mī-krŏmĭ-tər ]

A device for measuring very small distances, angles, or objects, especially one based on the rotation of a finely threaded screw, as in relation to a microscope.

Scientific definitions for micrometre (2 of 2)

[ mīkrō-mē′tər ]

A unit of length in the metric system equal to one millionth (10-6) of a meter. Also called micron
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.