cool
adjective
moderately cold; neither warm nor cold.
ultracool
-
a word derived from
cool.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
"While the sun is a bright, yellow dwarf star, TRAPPIST-1 is an ultracool red dwarf, meaning it is significantly smaller, cooler and dimmer than our sun," he explained.
From Science Daily ● Dec. 12, 2025
In 2021 Ferlaino and her team found that warming an ultracool quantum fluid of the magnetic rare earth element dysprosium could solidify it into a supersolid's distinctive peaks.
From Scientific American ● Jul. 31, 2023
LSR J1835+3259 is called an ultracool dwarf because it is much colder than most stars and looks mostly brown, but it's also tiny — just about the size of Jupiter.
From Salon ● May 17, 2023
The recently approved Johnson & Johnson vaccine, which doesn’t need ultracool storage and only requires one dose, would be particularly useful in rapid deployment to resource-poor settings around the world.
From Slate ● Mar. 12, 2021
I wanted to hear a big voice on the phone say “Yea, verily, this is me, God. It’s all good, my man, and will be ultracool in the end. Don’t worry about it.”
From "Bad Boy" by Walter Dean Myers
