calcium

noun

cal·​ci·​um ˈkal-sē-əm 

often attributive

: a metallic chemical element of the alkaline-earth group that occurs naturally only in combination and is essential to cellular functions in all known organisms see Chemical Elements Table

Examples of calcium in a Sentence

Her doctor said she should eat more foods that are high in calcium, such as milk and cheese.

Recent Examples on the Web

In addition to helping keep snails and slugs from snacking on your plants, Handley says, the eggshells will biodegrade naturally, and providing a small calcium boost to your garden soil. —Peg Aloi, The Spruce, 25 Apr. 2026

The nutritional nest egg is held together with a sprinkle of good fats and calcium-rich foods. —Sheah Rarback, Miami Herald, 24 Apr. 2026

This uses a chemical solution of 2% hydrogen peroxide with the abrasive calcium pyrophosphate to whiten your teeth. —Bestreviews, Chicago Tribune, 24 Apr. 2026

Research shows that sardines are an inexpensive source of omega-3s and other heart-healthy nutrients like calcium, potassium, and magnesium. —Stephanie Brown, Verywell Health, 24 Apr. 2026

Word History

Etymology

New Latin, from Latin calc-, calx lime

First Known Use

1808, in the meaning defined above

Phrases Containing calcium

• calcium carbide
• calcium carbonate
• calcium channel blocker
• calcium chloride
• calcium citrate
• calcium cyanamide
• calcium gluconate
• calcium hydroxide
• calcium hypochlorite
• calcium oxalate
• calcium oxide
• calcium phosphate
• calcium silicate
• calcium sulfate

Rhymes for calcium

• dicalcium
• tricalcium

Kids Definition

calcium

noun

cal·​ci·​um ˈkal-sē-əm 

: a silver-white soft metallic element that is found only in combination with other elements (as in limestone) and is one of the necessary elements making up the bodies of most plants and animals see element

Etymology

derived from Latin calc-, calx "lime" — related to calculate, chalk

Medical Definition

calcium

noun

cal·​ci·​um ˈkal-sē-əm 

often attributive

: a silver-white bivalent metallic element that is an alkaline earth metal, occurs only in combination, and is an essential constituent of most plants and animals

—symbol Ca see Chemical Elements Table