A cryogenic chamber was a chamber used in cryogenics to achieve low temperatures.
The Obsidian Order used cryogenic chambers to preserve biological subjects at cryogenic temperatures. In 2371, Corbin Entek showed Kira Nerys a cryogenic chamber that apparently contained her own corpse, in an attempt to convince that she was actually a surgically-altered Cardassian named Iliana Ghemor. (DS9: "Second Skin")