Type 1 is in reference to how well an area of the cervix called the Transformation Zone (TZ) is seen. A type 1 TZ means that all of this area is seen. There are also types 2 and 3 which also correspond to how much of the TZ is visible. The TZ is where the cervical smear test is carried out.
Information from the International Federation for Cervical Pathology and Colposcopy (IFCPC) have diagrams showing Types 1, 2 and 3 areas within their clinical guidance, you can see them here
