What does carious mean?
Carious is an adjective meaning decayed — specifically, affected by caries, the gradual destructive process that produces cavities in teeth and, less commonly, in bone. It belongs chiefly to the vocabulary of dentists, physicians, and dental researchers: X-rays are read for 'carious lesions,' teeth are classified as carious or sound, and treatment plans hinge on how far carious damage has progressed. The word derives from the Latin caries, meaning rot or decay, which also gives English the noun caries. Although it is precise and useful within clinical contexts, carious rarely appears outside professional writing; a general reader is more likely to meet it in an educational article about oral health than in ordinary speech. Its closest everyday equivalents are simply 'decayed' or 'full of cavities.'
adjectiveAffected with caries; decayed, especially of bone or teeth. In dentistry, it describes a tooth that has developed cavities or areas of decay.
- Of a tooth or bone: affected by decay (caries), typically forming cavities.
"The X-ray revealed several carious lesions on the patient's molars."
"Routine examination showed carious lesions on two lower molars."
"Untreated carious teeth can lead to infection of the surrounding gum and bone."
Every cavity your dentist has ever filled was technically a 'carious lesion' — a phrase borrowed straight from Latin, where 'caries' meant rot and putrefaction.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of carious
Carious comes from the Latin caries, meaning rottenness or decay, via the Late Latin adjective cariosus. It entered scientific English in the seventeenth century alongside the noun caries. The same Latin root underlies related terms such as caries itself, and it is cognate with words for decay and erosion in Romance languages like French carieux and Spanish carioso.
Related word forms
How carious is actually used
A technical term used almost exclusively in dentistry, medicine, and related scientific writing; it is rare in everyday conversation. It carries no emotional connotation but sounds formal and clinical to lay readers.
Easily confused with carious
'Curious' means eager to learn or strange, while 'carious' means decayed, especially of teeth or bone.
'Caries' is the noun naming the disease of tooth or bone decay itself, whereas 'carious' is the adjective describing tissue affected by it.