What is a Pap Smear?
The pap test or pap smear was invented in the early 1940s by a Greek doctor named George Papanicolaou. It is a painless and quick procedure to help screen for cervical cancer. During this process, some body cells from the cervix are taken for further analysis under a microscope. It does not diagnose cancerous cells, but searches for abnormal changes in the cervical areas. These cancerous or precancerous cells may indicate the presence of cancer. If these cells are found, further testing like a biopsy or colposcopy, may be suggested to diagnose the condition. 
Purpose of a Test Smear
As said above, a pap smear helps identify abnormal cervical changes, which would indicate whether cancer has already occured or is likely to occur. In many cases, the test can help find out and treat the condition before it grows and spread to other parts of the body. This procedure is often included in regular pelvic exams. Some women also take the pap smear to look for high-risk strains of HPV or human papillomavirus, which is linked to different cancers.