Data file saved by 4th Dimension, a software development program; stores the actual data referenced by a 4D database structure (.4DB) file; can be compacted by 4D Developer or 4D Server using the "Compact data file" command.
Program(s) that open 4dd files
Mac / Windows: 4D 4th Dimension software
Information from FileInfo.com - The File Extensions Resource.
http://www.fileinfo.com/extension/4dd
