<p><strong>Noun</strong></p><ul><li>A film bearing a miniature photographic copy of printed or other graphic matter, usually of a document, newspaper, or book pages, made for a library, archive, or the like.</li><li>A film, especially of motion-picture stock, on which microcopies are made.</li></ul><p><strong>Plural</strong></p><ul><li>Microns, micra.</li><li>Also called micrometer.</li></ul><p><strong>Definition</strong></p><ul><li>The millionth part of a meter (μ, mu).</li><li>A colloidal particle whose diameter is between 0.2 and 10 microns.</li><li>A very small unit of pressure, equal to that exerted by a column of mercury 1μ high.</li></ul>