1) Atom like 2) Microscopic 3) Subgross 1) Microscopic 2) Research 3) Visible under a microscope 
• (a.) Very small; visible only by the aid of a microscope; as, a microscopic insect. • (a.) Able to see extremely minute objects. • (a.) Of or pertaining to the microscope or to microscopy; made with a microscope; as, microscopic observation.
Synonym for microscopic ... 1. Of extremely small size, visible only by the aid of the microscope. ... 2. Pertaining or relating to a microscope or to microscopy. ... (18 Nov 1997) ...