barium

American  

[bair-ee-uhm, bar-] / ˈbɛər i əm, ˈbær- /

noun

Chemistry.

1. a whitish, malleable, active, divalent, metallic element, occurring in combination chiefly as barite or as witherite. Ba; 137.34; 56; 3.5 at 20°C.

---

barium British  

/ ˈbɛərɪəm /

noun

1. a soft silvery-white metallic element of the alkaline earth group. It is used in bearing alloys and compounds are used as pigments. Symbol: Ba; atomic no: 56; atomic wt: 137.327; valency: 2; relative density: 3.5; melting pt: 729°C; boiling pt: 1805°C

---

barium Scientific  

/ bâr′ē-əm /

1. A soft, silvery-white metallic element of the alkaline-earth group. It occurs only in combination with other elements, especially in barite. Barium compounds are used in x-raying the digestive system and in making fireworks and white pigments. Atomic number 56; atomic weight 137.33; melting point 725°C; boiling point 1,140°C; specific gravity 3.50; valence 2.

2. See Periodic Table

---

Etymology

Origin of barium

First recorded in 1800–10; bar(ytes) + -ium

Example Sentences

These are four endoscopy tests - upper endoscopy; lower endoscopy excluding colonoscopy; colonoscopy; and cystoscopy - and four radiology tests - CT scan; MRI scan; barium studies; and non-obstetric ultrasound.

From BBC • Nov. 25, 2025

The Environmental Protection Agency does not consider it a carcinogen; however, exposure to barium can cause gastrointestinal irritation, cardiovascular effects, kidney damage and respiratory problems.

From Los Angeles Times • May 4, 2025

The team built the materials on the superconductor YBCO, made of yttrium, barium, carbon and oxygen.

From Science Daily • May 20, 2024

The system can be adapted to detect other similar contaminants in water, including cadmium, copper, lithium, barium, cesium, and radium, Ranno says.

From Science Daily • May 14, 2024

She was given an endoscopy, an MRI, and a barium swallow to test her gastrointestinal tract.

From "Zeitoun" by Dave Eggers