cavity

noun

cav·​i·​ty ˈka-və-tē 

plural cavities

1

: an unfilled space within a mass

especially : a hollowed-out space

2

: an area of decay in a tooth : caries

Synonyms

• hole
• dent
• pit
• concavity

Examples of cavity in a Sentence

Some birds nest in tree cavities.

I had two cavities filled at the dentist's.

Recent Examples on the Web

Schumann Resonance Time Acceleration Schumann resonances are natural, low-frequency electromagnetic hums that form in the cavity between Earth’s surface and the ionosphere (50-600 miles above the surface). —Kaif Shaikh, Interesting Engineering, 4 Sep. 2025

In addition to maintaining good oral hygiene habits at home, such as brushing and flossing, experts recommend tactics like drinking plenty of water, limiting snacks and sugary foods, and quitting smoking to help prevent cavities. —Cristina Mutchler, Verywell Health, 4 Sep. 2025

Here’s to hoping Terri and Mel’s relationship is all smiles and no cavities. —Liza Esquibias, PEOPLE, 4 Sep. 2025

Jebel Marra volcano consists of a large crater, a 5-kilometre radius cavity, beneath the summit. —David Bressan, Forbes.com, 2 Sep. 2025

Word History

Etymology

borrowed from Middle French & Late Latin; Middle French cavité, borrowed from Late Latin cavitāt-, cavitās, from Latin cavus "hollow, concave" + -itāt-, -itās -ity — more at hole entry 1

First Known Use

1541, in the meaning defined at sense 1

Phrases Containing cavity

• abdominal cavity
• body cavity
• pelvic cavity
• segmentation cavity
• spinal cavity
• thoracic cavity

Rhymes for cavity

• gravity
• concavity
• depravity
• intracavity
• microgravity
• supergravity

Kids Definition

cavity

noun

cav·​i·​ty ˈkav-ət-ē 

plural cavities

1

: a hollow place

especially : an unfilled bodily space

lung cavity

2

: a hole hollowed out in a tooth by decay

Medical Definition

cavity

noun

cav·​i·​ty ˈkav-ət-ē 

plural cavities

1

: an unfilled space within a mass

2

: an area of decay in a tooth : caries