[mi.cro.some] n [G Mikrosom, fr. mikr- micr- + -som -some] (1885) 1: any of various minute cellular structures (as a ribosome)
2: a particle in a particulate fraction that is obtained by heavy centrifugation of broken cells and consists of various amounts of ribosomes, fragmented endoplasmic reticulum, and mitochondrial cristae -- mi.cro.som.al adj