Terminology of the disease currently known as chronic obstructive pulmonary disease has gone through a long and non-uniform development. Various definitions have been gradually developed and chronic bronchitis was separated from pulmonary emphysema. Various umbrella names have been suggested to unite this group of diseases. At present a classification based on World strategy for diagnosing, treatment and prevention of the chronic obstructive pulmonary disease from 2000 which has been published in our country too is used.