1. extremely cold; having a very low temperature
Usage: often used in scientific contexts

Examples

• The ultracold temperatures in Antarctica can reach minus 80 degrees Celsius.
• Scientists use ultracold atoms in quantum physics experiments.
• The ultracold winter made it dangerous to go outside without proper clothing.
• Researchers created an ultracold gas to study unusual states of matter.
• The ultracold storage facility preserves biological samples for decades.
• Ultracold neutron stars have temperatures near absolute zero.