tundra
One example of something cold that starts with the letter U is "ultracold." Ultracold refers to temperatures close to absolute zero, which is -273.15 degrees Celsius or 0 Kelvin. In physics and chemistry, ultracold temperatures are often used to study quantum phenomena and create exotic states of matter.
a umbrella
ushers
undergarnment
ur face
unicorn
yes
underwear
· jello · juice
Everest, MountEskimo Pie
North Pole.