submicroscopic(adj.)
英 [sʌbˌmaɪkrə'skɒpɪk] 美 [sʌbˌmaɪkrə'skɒpɪk]
also sub-microscopic, "too small to be seen, even with the aid of a microscope," 1881, from sub- "smaller (than)" + microscopic. Earliest scientific use is in reference to germs.
该词起源时间:1881年