a highly unstable radioactive element (the heaviest of the halogen series)
3
n a highly unstable radioactive element (the heaviest of the halogen series)
4
n a hollow globule of gas (e.g., air or carbon dioxide) n a speculative scheme that depends on unstable factors that the planner cannot control n an impracticable and illusory idea n a dome-shaped covering made of transparent glass or plastic v form, produce, or emit bubbles v flow in an irregular current with a bubbling noise v rise in bubbles or as if in bubbles v cause to form bubbles v expel gas from the stomach
5
n an unstable situation of extreme danger or difficulty n a crucial stage or turning point in the course of something
