Level 5 · word 11,132 of 20,000

radon

/ˈreɪˌdɑːn/ American
  • n.
Definition
  • n. a colorless radioactive gas found in small amounts in the earth
Example
Homeowners should test their basements for dangerous radon gas.
房主应该检测地下室是否存在危险的氡气。