what is a micrometer?
micrometer (Î¼m) [ 1 mÄ«kromâ²ÉtÉr] 2  1 an instrument used for measuring small angles or distances on objects being observed through a microscope or telescope. 3  2 [mÄ«â²krÅmÄâ²tÉr] , a unit of measurement, commonly referred to as a micron, that equals one millionth (10-6) of a meter.