According to a Cornell University Web page, the Pap smear, or Pap test, is named after Dr. Papanicolaou, known as Dr. Pap, who became a member of the university's Department of Anatomy in 1914. Papanicolaou developed the Pap smear.
This source explains that by 1946, the Pap smear gained traction in hospitals and began to be used as a method of detecting cervical cancer. The Pap smear was beneficial not only in detecting this cancer but also in detecting vaginal cancers and cancers of the endometrium and the fallopian tubes. The Pap smear has contributed to the dramatic reduction in the death rate of cervical cancer patients since the 1940s. At the time of the Pap smear's introduction, cervical cancer killed more women than any other illness.