Synonym for submicroscopic ... <optics> Particles which, although visible in the ultramicroscope, are too small to be resolved by visible light. This places their size between 0.2 Lm and 0.005 Lm. ... (05 Aug 1998) ... 
(ul″trә-mi″kro-skop´ik) too small to be seen with the ordinary light microscope.
(Humans as organisms) too small to be seen with a normal microscope. (Electron microscopes are usually used to study viruses)
Type: Term Pronunciation: ŭl′tră-mī-krō-skop′ik Synonyms: submicroscopic
[adj] - too small to be seen without an ultramicroscope
adjective too small to be seen without an ultramicroscope