an apparatus, usually automatic, maintaining a very low constant temperature.
Origin of cryostat
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
an apparatus for maintaining a constant low temperature or a vessel in which a substance is stored at a low temperature
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012