space that is surrounded by something
"The dentist found a small cavity in my tooth where decay had created an empty space surrounded by healthy enamel."
soft decayed area in a tooth; progressive decay can lead to the death of a tooth
"The dentist warned that leaving the cavity untreated could cause the tooth's nerve to die and require extraction."
(anatomy) a natural hollow or sinus within the body
"The dentist noticed a small cavity in the patient's molar where decay had formed a natural hollow within the tooth structure."
A hole or hollow depression in a solid object.
"The dentist filled the cavity in my tooth after drilling out the decayed area."
In plain English: A cavity is an empty space inside something, often referring to a hole that forms when teeth decay due to sugar and bacteria.
"The dentist filled his cavity with silver filling to stop the pain."
Usage: Use this term to describe any physical void within an object, such as the space inside your teeth caused by decay. It is often confused with "void," but while both mean emptiness, cavity specifically implies a contained hollow area rather than total absence of matter.
The word cavity entered English in the mid-1500s via Middle French and Late Latin. It originally described a hollow or excavated space, combining roots meaning "hollow" with a suffix indicating a state of being.