RhymeZone: microstructure definitions

Definitions of microstructure:

noun: The fine structure of a material or tissue as revealed by microscopy.
noun: (metallurgy) The fine structure of a pure metal or alloy, as revealed by magnifications of 25X or greater.
noun: (meteorology, oceanography) Fine-scale structure in such variables as temperature, salinity, velocity, etc.

(Definitions from Wiktionary)