What is meaning of Common Technical Document (CTD)?

The Common Technical Document (CTD) is a set of specification for application dossier for the registration of Medicines. And it is designed to be used across Europe, Japan and the United States.
It was developed by the European Medicines Agency (EMA,Europe), the Food and Drug Administration (FDA, U.S.) and the Ministry of Health, Labour and Welfare (Japan).
The CTD is maintained by the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH).
The agreement to assemble all the Quality, Safety and Efficacy information in a common format (called CTD – Common Technical Document ) has revolutionised the regulatory review processes, led to harmonised electronic submission that, in turn, enabled implementation of good review practices.
For industries, it has eliminated the need to reformat the information for submission to the different ICH regulatory authorities.