1. So small as to be invisible without a microscope
   "differences were microscopic";
   - microscopical
    
2. Visible under a microscope; using a microscope
   "The microscopic organisms were invisible to the naked eye";
   - microscopical
    
3. Of or relating to or used in microscopy
   "microscopic analysis";
   - microscopical
    
4. Extremely precise with great attention to details
   "examined it with microscopic care"

See also: little, precise, seeable, small, visible

Encyclopedia: Microscopic