Anatomy, gross: Better known among medical students simply as "gross", gross anatomy is the study of the form of structures that are large enough to be seen with the naked eye. Gross anatomy is distinct from microscopic anatomy (or histology) which involves structures too small to be seen by eye that must be viewed under the microscope. Traditionally, both gross and microscopic anatomy have been studied in the first year of medical school in the U.S. The most celebrated textbook of anatomy in the English-speaking world is Gray's Anatomy, still a useful reference book. The word "anatomy" comes from the Greek ana- meaning up or through + tome meaning a cutting. Anatomy was once a "cutting up" because the structure of the body was originally learned through dissecting it, cutting it up. The abbreviation for anatomy is anat.