thallium
/ˈθæliəm/
noun
- A soft, bluish-white metallic chemical element that is highly toxic. It is used in electronics, infrared detectors, and formerly in rat poison.
- The factory was fined for improperly disposing of waste containing thallium.
- Scientists use thallium in some types of medical imaging tests.
- Thallium is a heavy metal that can be dangerous if ingested.