A diagnostic smear is a medical test that involves the collection of cells from a patient's body, usually from the cervix or vagina, and examining them under a microscope. The term 'inkblot' is used to refer to this type of test, as the cells are spread out on a slide and then stained with a dye to make them easier to see. This test is used to detect any abnormalities in the cells, such as cancerous or precancerous cells, which can help diagnose and treat certain diseases.