micrometreWiktionary 原文英/ˈmaɪkrəˌmiːtə/美/ˈmaɪkrəˌmitər/构词拆解micromicro-前缀metremetre词干micro-(diminutive) Very small. · (metric units) One millionth.词源说明From micro- + metre.释义名词noun1An SI and mks unit of measure, the length of one-millionth of a metre. Symbol: μm, um, μ.