DDS vs BMP

Some people around here have mentioned that FSX is using .dds files as textures. Now I am wondering, for the sake of clearing it up for some people, what is the different between a .dds file and a .bmp file?
Flight Simulator and other chat
https://forums.simviation.com/phpBB3/
https://forums.simviation.com/phpBB3/viewtopic.php?f=21&t=58979